Fix for SavePreference not cleaning JNI correctly.
Fix for SavePreference not cleaning JNI correctly.

The result of a JNI call was not being deleted correctly, which causes
a memory leak.

Tested on Android.

Change-Id: I06c1ced775af60e78a08edc78c30a831269986ba

google/fplbase,google/fplbase,google/fplbase,google/fplbase