xfsprogs: Refactor release scripts to conform to using git archive

xfsprogs: Refactor release scripts to conform to using git archive

Refactored release scripts to conform to using git archive

When generating a release, there is a risk of missing necessary
source files. This is fixed by using git archive, which also
fixes the lack of conformity between the xfs utilities. As well,
some files may be stale during packaging. This is fixed with a
clean at the beginning of release generation.

Signed-off-by: Andrew Dahl <adahl@sgi.com>
Reviewed-by: Ben Myers <bpm@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>