GFS2: Combine gfs2_free_di with gfs2_free_uninit_di

GFS2: Combine gfs2_free_di with gfs2_free_uninit_di

Before this patch, function gfs2_free_di was 4 lines of code, and
one of those lines was to call gfs2_free_uninit_di. Although
unlikely, if function gfs2_free_uninit_di encountered an error
finding the block to be freed, the error was silently ignored by the
caller, which went ahead and improperly did a quota-change operation
and meta_wipe despite the error. This patch combines the two
functions into one to make the code more readable and fixes the bug
by returning from the combined function before it takes those next
incorrect steps.

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