gfs2: Remove unnecessary gfs2_qa_{get,put} pairs

We now get the quota data structure when opening a file writable and put it
when closing that writable file descriptor, so there no longer is a need for
gfs2_qa_{get,put} while we're holding a writable file descriptor.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Bob Peterson <rpeterso@redhat.com>