Don't update Android version on pulls

.travis.yml

@@ -179,8 +179,9 @@ before_script:
         export CONFIG=release;
     fi
 
-  # insert QGC version in AndroidManifest.xml
+  # Update QGC version in AndroidManifest.xml based on git tag. We do not do this on pull requests
-  - if [ "${SPEC}" = "android-clang" ]; then
+  # since it is likely the tags out out of date on the pull and may cause an error.
+  - if [ "${SPEC}" = "android-clang"  && "${TRAVIS_PULL_REQUEST}" = "false" ]]; then
         git remote set-branches origin 'master' &&
         git fetch --tags origin master &&
         ./tools/update_android_version.sh ${BITNESS} ${TRAVIS_BRANCH};