Comment 9 for bug 537228

testcase:
$ sudo apt-get install eagle
$ wget http://ftp.debian.org/debian/pool/non-free/e/eagle/eagle-data_5.9.0-1_all.deb
$ gdebi eagle-data_5.9.0-1_all.deb
 -> message stating that eagle-data 5.9.0 will break eagle 5.7.0 should be received
 -> without attached fixes, we get crash

SRU justification:
 - motivation: without fix, users installing a package via GDebi which will break dependencies, will not know why the package can't be installed, since GDebi will crash in this case
 - intrusiveness: the fix is minimal (one-line of code) which affects only the code invoked when packages can't be installed due to dependency breakage
 - potential collateral: none, as there are no child or shared packages of this