Update travis to qt5.9.2

.ci/linux/install-deps.sh

 #!/usr/bin/env bash
 
-sudo add-apt-repository -y ppa:beineri/opt-qt58-trusty
+sudo add-apt-repository -y ppa:beineri/opt-qt592-trusty
 sudo add-apt-repository -y ppa:george-edison55/cmake-3.x
 sudo apt-get update -qq
-sudo apt-get install -qq -y qt58base qt58tools cmake liblmdb-dev
+sudo apt-get install -qq -y qt59base qt59tools cmake liblmdb-dev

.travis.yml

@@ -21,7 +21,7 @@ install:
     - if [ $TRAVIS_OS_NAME == osx ]; then export CMAKE_PREFIX_PATH=/usr/local/opt/qt5; fi
     - if [ $TRAVIS_OS_NAME == linux ]; then ./.ci/linux/install-deps.sh; fi
 before_script:
-    - if [ $TRAVIS_OS_NAME == linux ]; then source /opt/qt58/bin/qt58-env.sh; fi
+    - if [ $TRAVIS_OS_NAME == linux ]; then source /opt/qt59/bin/qt59-env.sh; fi
     - cmake -H. -Bbuild -DCMAKE_BUILD_TYPE=Release
 script:
     - make -C build -j2