Fix Travis by using a PPA to install QT. (#4269)

.travis.yml

@@ -34,12 +34,6 @@ before_install:
     fi;
 
 install:
-  - if [ "$TRAVIS_OS_NAME" = "linux" ]; then
-      wget http://download.qt.io/official_releases/online_installers/qt-unified-linux-x64-online.run ;
-      chmod a+x ./qt-unified-linux-x64-online.run ;
-      QT_QPA_PLATFORM=minimal QTVER="${QTVER//.}" travis_wait 60 ./qt-unified-linux-x64-online.run --script qt-installer-noninteractive.qs --no-force-installations --verbose ;
-    fi;
-
   # Install updated libglew-dev since the version provided by trusty is outdated
   - if [ "$TRAVIS_OS_NAME" = "linux" ]; then
       wget https://mirrors.kernel.org/ubuntu/pool/universe/g/glew/libglew-dev_2.0.0-5_amd64.deb;
@@ -99,6 +93,7 @@ addons:
       - ubuntu-toolchain-r-test
       - llvm-toolchain-trusty-4.0
       - sourceline: 'ppa:jonathonf/binutils' # We need to update binutils to a newer version to link against the ffmpeg libs on.
+      - sourceline: 'ppa:beineri/opt-qt-5.10.1-trusty' # <<WARNING>>: This needs to be updated manually whenever the QT Version changes. Add QT PPA since the installer is quite bad.
     packages:
       - binutils
       - cmake
@@ -120,8 +115,8 @@ addons:
       - libstdc++-5-dev
       - lib32stdc++6
       - zlib1g-dev
-      # We need to install qt 5.10.1 manually because the version trusty provides is too old.
-      #- qtbase5-dev
+      # From the beineri PPA
+      - qt510-meta-minimal # <<WARNING>>: This needs to be updated manually whenever the QT Version changes.
       - libudev-dev
       - libevdev-dev
       - libpulse-dev