GFS2: Refactor gfs2_remove_from_journal

This patch makes two simple changes to function gfs2_remove_from_journal.
First, it removes the parameter that specifies the transaction.
Since it's always passed in as current->journal_info, we might as well
set that in the function rather than passing it in. Second, it changes
the meta parameter to use an enum to make the code more clear.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Acked-by: Steven Whitehouse <swhiteho@redhat.com>