scripts/get_maintainer.pl: add sections in pattern match depth order

Before this change, matched sections were added in the order
of appearance in the normally alphabetic section order of
the MAINTAINERS file.

For instance, finding the maintainer for drivers/scsi/wd7000.c
would first find "SCSI SUBSYSTEM", then "WD7000 SCSI SUBSYSTEM",
then "THE REST".

before patch:

$ ./scripts/get_maintainer.pl --nogit -f drivers/scsi/wd7000.c
James E.J. Bottomley <James.Bottomley@HansenPartnership.com>
Miroslav Zagorac <zaga@fly.cc.fer.hr>
linux-scsi@vger.kernel.org
linux-kernel@vger.kernel.org

get_maintainer.pl now selects matched sections by longest pattern match.
Longest is the number of "/"s and any specific file pattern.

This changes the example output order of MAINTAINERS to whatever is
selected in "WD7000 SUBSYSTEM", then "SCSI SYSTEM", then "THE REST".

after patch:

$ ./scripts/get_maintainer.pl --nogit -f drivers/scsi/wd7000.c
Miroslav Zagorac <zaga@fly.cc.fer.hr>
James E.J. Bottomley <James.Bottomley@HansenPartnership.com>
linux-scsi@vger.kernel.org
linux-kernel@vger.kernel.org

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>