rc-file: Fix attica Qt4 config.

Attica for Qt4 requires being built with -DQT4_BUILD=TRUE on the cmake
command line, otherwise it will use Qt5 if it can find it.

Thanks to Riccardo Bellini for the report.

BUG:329797
FIXED-IN:1.16

kdesrc-buildrc-sample

@@ -161,6 +161,11 @@ module-set
     # cmake-options -DCMAKE_BUILD_TYPE=Debug
 end module-set
 
+# "options" requires kdesrc-build on or after 11-Jan-2014.
+options attica
+    cmake-options -DQT4_BUILD=TRUE # Required if both Qt4 and 5 are present.
+end options
+
 # Phonon is the KDE multimedia layer, which is occasionally synced to Qt.
 # It is required for the KDE libraries, and a specific backend for your system
 # is also required. For Linux users, this means either phonon-gstreamer or