Revert "PA-Vendor: Built-in superuser"

This reverts commit 43a2bd2b7953ee80aa17b3c86e38d41c2f80c991.
Softbank carrier overlay that fixes Mms User Agent for both Mms.apk & Hangouts

This forces set UA string to Nexus5 for SoftBank MCC:440 MCN:20.
Tested send/receive & confirmed working by yours truly.

Change-Id: I1831c329eb38507a957111052bb5f56350c49361
Merge branch 'kitkat' of github.com:AOSPA-legacy/android_vendor_pa into kk4.4