Fix Segmentation fault while data in Package.gz is not good

Fix Segmentation fault while data in Package.gz is not good

While setting up a personal opkg feed, I encountered a crash in opgk
when trying to install the package from the repository. Instead of an
error message from opkg, it just gave me "Segmentation fault" and
exited.

Thanks to EdorFaus <edorfaus@gmail.com>
http://groups.google.com/group/opkg-devel/browse_thread/thread/9620711475fa98d2

git-svn-id: http://opkg.googlecode.com/svn/trunk@218 e8e0d7a0-c8d9-11dd-a880-a1081c7ac358