Make plugin for QCustomPlot disabled by default.

plugins/CMakeLists.txt

@@ -22,8 +22,8 @@
 IF(PYTHONQT_FOUND)
   ADD_OPTIONAL_DEPENDENCY("QGVCore")
 
-  SET(BUILD_PY_QGV       ${QGVCORE_FOUND}
-    CACHE BOOL "Build PyQGV plugin")
+  OPTION(BUILD_PY_QGV "Build PyQGV plugin" ${QGVCORE_FOUND})
+  OPTION(BUILD_PY_QCUSTOM_PLOT "Build PyQCustomPlot plugin" OFF)
 ENDIF(PYTHONQT_FOUND)
 
 IF(PYTHONQT_FOUND AND BUILD_PY_QGV)