Fixed uninstallPackage

Changed uninstallPackage from STUBS_APK to STUBS_PKG

Bug: 62987793
Test: run cts -o -d -m CtsSyncContentHostTestCases
      run cts -o -d -m CtsSecurityTestCases -t android.security.cts.PackageSignatureTest

Change-Id: I9c27209e1983137d50eefe3931a16e6688acddc9
1 file changed