An invalid project lead will cause the browse projects page search functionality to stop working

Steps to Reproduce

1. Create a few Projects.
2. Modify the database record for one of the projects such that the lead field point to a non-existing user.
3. Go to the Browse Projects page and type a few character in the search box to narrow down the list of projects on the page.

Actual Results

• Results are not filtered and you should see a javascript error in the console similar to:

Uncaught TypeError: Cannot read property 'toLowerCase' of null(anonymous function) @ jira.webresources:browseprojects.js?locale=en-US:9filterCollection @ jira.webresources:browseprojects.js?locale=en-US:9B @ batch.js?atlassian.aui.raphael.disabled=true&locale=en-US:636Z.Events.trigger @ batch.js?atlassian.aui.raphael.disabled=true&locale=en-US:636l.extend.set @ batch.js?atlassian.aui.raphael.disabled=true&locale=en-US:636inputsContains @ jira.webresources:browseprojects.js?locale=en-US:30w @ batch.js?atlassian.aui.raphael.disabled=true&locale=en-US:536

Expected Results

• The list of projects is filtered according to the search criteria without any errors.

Workaround / Notes

• Adjusting the project lead username so that it matches a user known to JIRA will fix the issue.