[OS X] Use Qt 5.5 on CI

Newer Qt versions require C++11.

CI/before_install.osx.sh

@@ -1,10 +1,11 @@
 #!/bin/sh
 
 brew update
+
 brew rm cmake || true
 brew rm pkgconfig || true
 brew rm qt5 || true
-brew install cmake pkgconfig qt5
+brew install cmake pkgconfig qt55
 
 curl http://downloads.openmw.org/osx/dependencies/openmw-deps-263d4a8.zip -o ~/openmw-deps.zip
 unzip ~/openmw-deps.zip -d /private/tmp/openmw-deps > /dev/null

CI/before_script.osx.sh

@@ -4,7 +4,7 @@ export CXX=clang++
 export CC=clang
 
 DEPENDENCIES_ROOT="/private/tmp/openmw-deps/openmw-deps"
-QT_PATH="/usr/local/opt/qt5"
+QT_PATH="/usr/local/opt/qt55"
 
 mkdir build
 cd build