Catch exception when testing find_sdk_tools_cmd
Catch exception when testing find_sdk_tools_cmd

In 1c7df94e find_sdk_tools_cmd was changed to throw an FDroidException
when the sdk tools where not found instead of returning None.

fdroidtravis/fdroidserver,f-droid/fdroidserver,fdroidtravis/fdroidserver,f-droid/fdroid-server,fdroidtravis/fdroidserver,f-droid/fdroid-server,f-droid/fdroidserver,f-droid/fdroidserver,fdroidtravis/fdroidserver,f-droid/fdroidserver,f-droid/fdroidserver,f-droid/fdroid-server,f-droid/fdroid-server,f-droid/fdroid-server