"force" mount option) if it detects that the HFS+ volume has a journal. 
The code was unconditionally assuming that the volume had a jounal if the
journal attribute was set in the volume header.  However, the volume also
has to have a non-zero journal info block to actually have a journal.

In this patch, I refactored the journal detection into a function since
the logic is used twice.  The journal detection also uses the better logic
to determine if there is a journal.
Signed-off-by: Warren Turkal <wt@penguintechs.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>