don't fail updating android version on PRs

-fixes #2955

.travis.yml

@@ -114,7 +114,7 @@ before_script:
   - if [ "${CONFIG}" != "doxygen" ]; then mkdir ${SHADOW_BUILD_DIR} && cd ${SHADOW_BUILD_DIR} && qmake -r ${TRAVIS_BUILD_DIR}/qgroundcontrol.pro CONFIG+=${CONFIG} CONFIG+=WarningsAsErrorsOn -spec ${SPEC}; fi
 
 script:
-  - cd ${TRAVIS_BUILD_DIR} && ./tools/update_android_version.sh
+  - if [ "${TRAVIS_OS_NAME}" = "android" ]; then cd ${TRAVIS_BUILD_DIR} && ./tools/update_android_version.sh; fi
   - echo 'Building QGroundControl' && echo -en 'travis_fold:start:script.1\\r'
   - if [ "${CONFIG}" != "doxygen" ]; then cd ${SHADOW_BUILD_DIR} && make -j4; fi
   - if [ "${CONFIG}" = "doxygen" ]; then cd ${TRAVIS_BUILD_DIR}/src && doxygen documentation.dox; fi

android/AndroidManifest.xml

 <?xml version="1.0"?>
-<manifest package="org.mavlink.qgroundcontrol" xmlns:android="http://schemas.android.com/apk/res/android" android:versionName="2.8.0" android:versionCode="2152" android:installLocation="auto">
+<manifest package="org.mavlink.qgroundcontrol" xmlns:android="http://schemas.android.com/apk/res/android" android:versionName="2.9.4-184-gda30c6b" android:versionCode="2506" android:installLocation="auto">
     <application android:hardwareAccelerated="true" android:name="org.qtproject.qt5.android.bindings.QtApplication" android:label="-- %%INSERT_APP_NAME%% --" android:icon="@drawable/icon">
         <activity android:configChanges="orientation|uiMode|screenLayout|screenSize|smallestScreenSize|locale|fontScale|keyboard|keyboardHidden|navigation" android:name="org.qgroundcontrol.qgchelper.UsbDeviceJNI" android:label="-- %%INSERT_APP_NAME%% --" android:screenOrientation="sensorLandscape" android:launchMode="singleTask" android:keepScreenOn="true">
             <intent-filter>

tools/update_android_version.sh

 #!/usr/bin/env bash
 
+# this requires `master` in the git tree
+#  travis-ci branch builds are unable to set the version properly
+
 MANIFEST_FILE=android/AndroidManifest.xml
 
 VERSIONCODE=`git rev-list master --first-parent --count`
@@ -13,7 +16,7 @@ if [ -n "$VERSIONCODE" ]; then
 	echo "Android version: ${VERSIONCODE}"
 else
 	echo "Error versionCode empty"
-	exit 1
+	exit 0 # don't cause the build to fail
 fi
 
 if [ -n "$VERSIONNAME" ]; then
@@ -21,5 +24,5 @@ if [ -n "$VERSIONNAME" ]; then
 	echo "Android name: ${VERSIONNAME}"
 else
 	echo "Error versionName empty"
-	exit 1
+	exit 0 # don't cause the build to fail
 fi