hfsplus: handle match_strdup failure

fs/hfsplus/options.c (hfsplus_parse_options): Handle match_strdup failure.

Signed-off-by: Jim Meyering <meyering@redhat.com>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>