jbd2: fix duplicate debug label for phase 2

Currently we see this output:

  $git grep phase fs/jbd2
  fs/jbd2/commit.c:       jbd_debug(3, "JBD2: commit phase 1\n");
  fs/jbd2/commit.c:       jbd_debug(3, "JBD2: commit phase 2\n");
  fs/jbd2/commit.c:       jbd_debug(3, "JBD2: commit phase 2\n");
  fs/jbd2/commit.c:       jbd_debug(3, "JBD2: commit phase 3\n");
  fs/jbd2/commit.c:       jbd_debug(3, "JBD2: commit phase 4\n");
  [...]

There is clearly a duplicate label for phase 2, and they are
both active (i.e. not in #if ... #else block).  Rename them to
be "2a" and "2b" so the debug output is unambiguous.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

fs/jbd2/commit.c

@@ -542,7 +542,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
 	wake_up(&journal->j_wait_transaction_locked);
 	write_unlock(&journal->j_state_lock);
 
-	jbd_debug(3, "JBD2: commit phase 2\n");
+	jbd_debug(3, "JBD2: commit phase 2a\n");
 
 	/*
 	 * Now start flushing things to disk, in the order they appear
@@ -557,7 +557,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
 					  &log_bufs, WRITE_SYNC);
 	blk_finish_plug(&plug);
 
-	jbd_debug(3, "JBD2: commit phase 2\n");
+	jbd_debug(3, "JBD2: commit phase 2b\n");
 
 	/*
 	 * Way to go: we have now written out all of the data for a