Select Ruby 2.1.1

.travis.yml

 language: cpp
 
-rvm:
-  - rbx-2.1.1
-
 git:
   depth: 500
 
@@ -69,9 +66,9 @@ cache:
 
 before_install:
   - cd ${TRAVIS_BUILD_DIR} && git fetch --unshallow && git fetch --all --tags
-  - if [ "${TRAVIS_OS_NAME}" = "linux" ]; then mkdir -p ~/.config/QtProject/ && cp ${TRAVIS_BUILD_DIR}/test/qtlogging.ini ~/.config/QtProject/; fi
+  - if [ "${TRAVIS_OS_NAME}" = "linux" ]; then rvm install 2.1.1 && mkdir -p ~/.config/QtProject/ && cp ${TRAVIS_BUILD_DIR}/test/qtlogging.ini ~/.config/QtProject/; fi
   - if [ "${TRAVIS_OS_NAME}" = "osx" ]; then mkdir -p ~/Library/Preferences/QtProject/ && cp ${TRAVIS_BUILD_DIR}/test/qtlogging.ini ~/Library/Preferences/QtProject/; fi
-  - if [ "${TRAVIS_OS_NAME}" = "android" ]; then wget https://s3-us-west-2.amazonaws.com/qgroundcontrol/dependencies/gstreamer-1.0-android-armv7-1.5.2.tar.bz2 && mkdir -p ${TRAVIS_BUILD_DIR}/gstreamer-1.0-android-armv7-1.5.2 && tar jxf gstreamer-1.0-android-armv7-1.5.2.tar.bz2 -C ${TRAVIS_BUILD_DIR}/gstreamer-1.0-android-armv7-1.5.2; fi
+  - if [ "${TRAVIS_OS_NAME}" = "android" ]; then rvm install 2.1.1 && wget https://s3-us-west-2.amazonaws.com/qgroundcontrol/dependencies/gstreamer-1.0-android-armv7-1.5.2.tar.bz2 && mkdir -p ${TRAVIS_BUILD_DIR}/gstreamer-1.0-android-armv7-1.5.2 && tar jxf gstreamer-1.0-android-armv7-1.5.2.tar.bz2 -C ${TRAVIS_BUILD_DIR}/gstreamer-1.0-android-armv7-1.5.2; fi
 
 install:
   - if [[ "${TRAVIS_OS_NAME}" = "linux" && "${CONFIG}" != "doxygen" ]]; then