[BUGFIX] Display error message for "Check for broken extensions"

If you try to uninstall an extension, which is needed by another one,
the process triggers an error without any information for the user. This
patch catches the exception and shows it in frontend.

Releases: master, 6.2
Resolves: #63672
Change-Id: I339b3cb533e7ec22cbdd27a2661e1b775ac665c0
Reviewed-on: http://review.typo3.org/37024


Reviewed-by: Alexander Opitz <opitz.alexander@googlemail.com>
Tested-by: Alexander Opitz <opitz.alexander@googlemail.com>
Reviewed-by: Markus Klein <klein.t3@reelworx.at>
Tested-by: Markus Klein <klein.t3@reelworx.at>