BUG: Fix typo reported in #6790.

Modules/FindQt4.cmake

@@ -1244,7 +1244,7 @@ IF (QT4_QMAKE_FOUND)
                   GET_FILENAME_COMPONENT(_basename ${_current_MOC} NAME_WE)
                   SET(_header ${_abs_PATH}/${_basename}.h)
                   SET(_moc    ${CMAKE_CURRENT_BINARY_DIR}/${_current_MOC})
-                  QT4_CREATE_MOC_COMMAND(${_header} ${_moc} "${moc_INCS}" "")
+                  QT4_CREATE_MOC_COMMAND(${_header} ${_moc} "${_moc_INCS}" "")
                   MACRO_ADD_FILE_DEPENDENCIES(${_abs_FILE} ${_moc})
                ENDFOREACH (_current_MOC_INC)
             ENDIF(_match)