Minimal fixes needed to install local deb packages

I needed to make these changes to get installing of local deb packages working. It's pretty much the minimum amount of changes but might be useful is someone else has the same problems as me:

* Package did not have version info which caused aminator to crash
* deb_package_metadata tried to read package info as if the package was a global one
* return value of apt_get_localinstall did not match that of apt_get_install which caused aminator to crash