Not authorized to install Support Tools Plugin when trying to update the add-on

Summary

FishEye throws an error when trying to update the Support Tools Plugin, displaying a message that says "Not authorized to install Support Tools Plugin".

Environment

• User logged in as the password-only admin exclusively (no real user logged in).

Steps to Reproduce

1. Being completely logged out, log in with the password-only admin.
2. Go to Administration > Manage add-ons and try to Update the Support Tools Plugin.

Expected Results

• The add-on is properly updated.

Actual Results

• In the UI, FishEye displays the following message:
  
• The below exception is thrown in the atlassian-fisheye-<date>.log file:

  2016-10-17 10:44:49,137 WARN  [UpmAsynchronousTaskManager:thread-2 ] com.atlassian.upm.core.rest.resources.install.InstallTask InstallTask-run - Unpermitted to install add-on
  com.atlassian.upm.core.rest.resources.permission.PermissionException: Must have permission to access this resource.
  	at com.atlassian.upm.core.rest.resources.permission.PermissionException.unauthorized(PermissionException.java:33) [atlassian-universal-plugin-manager-plugin-2.20.5_1475066100000.jar:?]
  	at com.atlassian.upm.core.rest.resources.permission.PermissionEnforcer.handleError(PermissionEnforcer.java:113) [atlassian-universal-plugin-manager-plugin-2.20.5_1475066100000.jar:?]
  	at com.atlassian.upm.core.rest.resources.permission.PermissionEnforcer.enforceInProcessInstallationFromUriPermission(PermissionEnforcer.java:94) [atlassian-universal-plugin-manager-plugin-2.20.5_1475066100000.jar:?]
  	at com.atlassian.upm.core.rest.resources.install.InstallFromUriTask$1.apply(InstallFromUriTask.java:83) [atlassian-universal-plugin-manager-plugin-2.20.5_1475066100000.jar:?]
  	at com.atlassian.upm.core.rest.resources.install.InstallFromUriTask$1.apply(InstallFromUriTask.java:50) [atlassian-universal-plugin-manager-plugin-2.20.5_1475066100000.jar:?]
  	at com.atlassian.upm.api.util.Either$Right.fold(Either.java:160) [atlassian-universal-plugin-manager-plugin-2.20.5_1475066100000.jar:?]
  	at com.atlassian.upm.core.rest.resources.install.InstallFromUriTask.executeTask(InstallFromUriTask.java:49) [atlassian-universal-plugin-manager-plugin-2.20.5_1475066100000.jar:?]
  	at com.atlassian.upm.core.rest.resources.install.InstallTask.run(InstallTask.java:81) [atlassian-universal-plugin-manager-plugin-2.20.5_1475066100000.jar:?]
  	at com.atlassian.upm.core.async.AsynchronousTaskManager.executeTask(AsynchronousTaskManager.java:124) [atlassian-universal-plugin-manager-plugin-2.20.5_1475066100000.jar:?]
  	at com.atlassian.upm.core.async.AsynchronousTaskManager$1.call(AsynchronousTaskManager.java:102) [atlassian-universal-plugin-manager-plugin-2.20.5_1475066100000.jar:?]
  	at com.atlassian.upm.core.async.AsynchronousTaskManager$1.call(AsynchronousTaskManager.java:99) [atlassian-universal-plugin-manager-plugin-2.20.5_1475066100000.jar:?]
  	at com.atlassian.sal.core.executor.ThreadLocalDelegateCallable.call(ThreadLocalDelegateCallable.java:38) [sal-fisheye-plugin-4.2.0-20160928073034_1475066100000.jar:?]
  	at java.util.concurrent.FutureTask.run(FutureTask.java:266) [?:1.8.0_102]
  	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142) [?:1.8.0_102]
  	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) [?:1.8.0_102]
  	at java.lang.Thread.run(Thread.java:745) [?:1.8.0_102]
  

Notes

• This happens when trying to update the add-on with the password-only admin, as FishEye relies on a real user, who's an administrator, to allow the update.

Workaround

Create a real user and turn him administrator:

1. Go to Administration > Users and create a new user.
2. Go to Administration > Administrators and turn this user an admin.
3. Log in as this user, then try to update the add-on again.
4. The update still may fail with the error described at https://jira.atlassian.com/browse/FE-5629, for which you can follow the workaround suggested on that report.