xfsprogs: fix permissions on files installed by libtoolize

xfsprogs: fix permissions on files installed by libtoolize

Libtoolize installs some set of AUX files from its system package.
Not all distributions have the same permissions set on these files.
For example, read-only libtoolize system package will copy those
files without write permissions. This causes build to fail as next
line copies ./include/install-sh over ./install-sh which is not
writable.

Fix this by setting permission explicitly on files copied by
libtoolize.

Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrey Albershteyn <aalbersh@redhat.com>