jbd2: Export jbd2_log_start_commit to fix ext4 build

    
    This fixes:
    ERROR: "jbd2_log_start_commit" [fs/ext4/ext4.ko] undefined!
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>

fs/jbd2/journal.c

@@ -78,6 +78,7 @@ EXPORT_SYMBOL(jbd2_journal_errno);
 EXPORT_SYMBOL(jbd2_journal_ack_err);
 EXPORT_SYMBOL(jbd2_journal_clear_err);
 EXPORT_SYMBOL(jbd2_log_wait_commit);
+EXPORT_SYMBOL(jbd2_log_start_commit);
 EXPORT_SYMBOL(jbd2_journal_start_commit);
 EXPORT_SYMBOL(jbd2_journal_force_commit_nested);
 EXPORT_SYMBOL(jbd2_journal_wipe);