Solve minor bug in rapidjson installation.

Author: viferga

InstallRapidJSON.cmake

@@ -34,7 +34,7 @@ if(NOT RAPIDJSON_FOUND OR USE_BUNDLED_RAPIDJSON)
 		URL_MD5			${RAPIDJSON_URL_MD5}
 		CMAKE_ARGS
 			-DCMAKE_INSTALL_PREFIX=<INSTALL_DIR>
-			-RAPIDJSON_BUILD_DOC=Off
+			-DRAPIDJSON_BUILD_DOC=Off
 			-DRAPIDJSON_BUILD_EXAMPLES=Off
 			-DRAPIDJSON_BUILD_TESTS=Off
 		TEST_COMMAND	""