Fix memory leak in file open menu (#29)
Fix memory leak in file open menu (#29)

AppInfoAction stores a GAppInfo and updates the reference count in the
constructor and destructor. Nevertheless, the GAppInfos were later not
finalized because they still were referenced from their original list.

Found by Valgrind.
vc-01/libfm-qt,vc-01/libfm-qt,lxde/libfm-qt,lxde/libfm-qt