aiaiai: use correct backref numbers for $m and $n

Fix subject handling of X/n patches which incorrectly pulled the subject
out using the wrong prefix.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Fixes: 3531d588c7f4 ("aiaiai-email-sh-functions: allow patches without PATCH prefix")
1 file changed