contrib/rpm: fix obtaining SOURCE via git-archive
- when user provided a $SOURCE argument, do call abs_path on
it. abs_path allows the user to provide relative paths in
the original directory.
- don't call abs_path on "$GITDIR/NetworkManager-$VERSION".tar.xz
abs_path is there to verify user input and it will abort the script
if the file doesn't exist.
- when creating a temporary tarball via git-archive, put it
into the output directory and not overwriting files in
$GITDIR.
- fix abs_path to return an error code and let callers abort
the script
- add a new parameter $SOURCE_FROM_GIT so that you can control
whether git-archive is used. You can now specify either $SOURCE
or $SOURCE_FROM_GIT. In case of absence of both, it tries to
detect a tar file in the $GITDIR directory.
Fixes:
9e9ec1a3da47c07bb0bb0b42014292a8df1c1e0b