Issue Summary

When Sharedhome become unavailable Bamboo administration configurations reverted to default values even after sharedhome become available. 

This is reproducible on Data Center: Yes

Steps to Reproduce

1. Setup Bamboo with some customer admin configurations, eg: edit the Bamboo instance details name value to a custom value
2. Make the sharedhome folder unavailable by rename it or moving it
3. Check the Bamboo UI after 90 secs (Bamboo ADMINISTRATOR_CONFIGURATION_CACHE_EXPIRY_AFTER_WRITE_SECONDS is 90 secs), the settings are defaulted
4. Put back the Sharedhome folder
5. Wait more than 90 secs (Bamboo ADMINISTRATOR_CONFIGURATION_CACHE_EXPIRY_AFTER_WRITE_SECONDS is 90 secs)
6. check the Bamboo admin configurations , it will be still showing the default values

Expected Results

Bamboo admin configurations should be read again when Sharedhome becomes available and values should reflect in Administration UI.

Actual Results

Bamboo admin configurations reverted to the Default values

Workaround

Restart Bamboo Application when sharedhome become available.