Travis, OSX: Save some minutes by using official Qt just for deploys.

- As we just deploy on new tags so all other builds can use Homebrew qt that is much smaller download.

.travis.yml

@@ -32,19 +32,26 @@ install:
   - if [[ "$TRAVIS_OS_NAME" == "osx" ]]; then
          echo "Calling brew update...";
          brew update;
+         brew outdated openssl || brew upgrade openssl;
          brew install ccache;
          PATH="/usr/local/opt/ccache/libexec:$PATH";
 
          if [[ "$QT" == "qt58" ]]; then
               QT_VER=5.8;
-              export QTDIR="$HOME/Qt/$QT_VER/clang_64";
-              brew outdated openssl || brew upgrade openssl;
-              QT_INSTALLER_FILE_NAME=qt-opensource-mac-x64-clang-$QT_VER.0;
-              wget "http://download.qt.io/official_releases/qt/$QT_VER/$QT_VER.0/$QT_INSTALLER_FILE_NAME.dmg";
-              hdiutil attach -noverify $QT_INSTALLER_FILE_NAME.dmg;
-              QT_INSTALLER=/Volumes/$QT_INSTALLER_FILE_NAME/$QT_INSTALLER_FILE_NAME.app/Contents/MacOS/$QT_INSTALLER_FILE_NAME;
-              echo "Silently installing Qt...";
-              travis_wait $QT_INSTALLER --script $QZ_DIR/mac/qt-mac-silent-install.qs;
+              if [ -z "$TRAVIS_TAG" ]; then
+                  echo "Using Homebrew Qt...";
+                  brew install qt5;
+                  export QTDIR=/usr/local/opt/qt5;
+              else
+                  echo "Using official Qt installer...";
+                  QT_INSTALLER_FILE_NAME=qt-opensource-mac-x64-clang-$QT_VER.0;
+                  wget "http://download.qt.io/official_releases/qt/$QT_VER/$QT_VER.0/$QT_INSTALLER_FILE_NAME.dmg";
+                  hdiutil attach -noverify $QT_INSTALLER_FILE_NAME.dmg;
+                  QT_INSTALLER=/Volumes/$QT_INSTALLER_FILE_NAME/$QT_INSTALLER_FILE_NAME.app/Contents/MacOS/$QT_INSTALLER_FILE_NAME;
+                  echo "Silently installing Qt...";
+                  travis_wait $QT_INSTALLER --script $QZ_DIR/mac/qt-mac-silent-install.qs;
+                  export QTDIR="$HOME/Qt/$QT_VER/clang_64";
+              fi
          fi
     fi