Calculator: Remove unused strings

Change-Id: Idc8301a567469f26a7c1bde35427fd320be64a37
Automatic translation import

Change-Id: Iee37c6313e0dee641231add2267adcfeef6af6b5
Merge branch 'cm-11.0' of https://github.com/CyanogenMod/android_packages_apps_Calculator into cm-11.0