Update .travis.yml

Author: janakarana

.travis.yml

@@ -38,7 +38,7 @@ script:
  - if [ "$OS" = "osx" ]; then
      qmake -config release -spec macx-xcode src/MieSimulatorGUI.pro;
      xcodebuild -configuration "Release" -list -project MieSimulatorGUI_continuous.xcodeproj;
-     xcodebuild -scheme MieSimulatorGUI_continuous build;      
+     xcodebuild -scheme MieSimulatorGUI_continuous -configuration "Release";      
    fi