MTNL apn fix

MTNL uses 68 and 69 MNC respectively in Delhi and mumbai

forward port of this change
http://review.cyanogenmod.org/#/c/27022/

Signed-off-by: Arnav Gupta <championswimmer@gmail.com>
Merge remote-tracking branch 'cyanogen/cm-10.1' into cm-10.1