Use CPACK_RPM_FILE_NAME="RPM-DEFAULT"

This has been implemented in for cmake-3.6 to match distro version
of what the filename should look like.

Thanks to Domen Vranka for the suggestion.

cmake/cpack_rpm.cmake

@@ -28,7 +28,11 @@ SET(CPACK_COMPONENTS_ALL Server ManPagesServer IniFiles Server_Scripts
                          Common Client SharedLibraries)
 
 SET(CPACK_RPM_PACKAGE_NAME "MariaDB")
-SET(CPACK_PACKAGE_FILE_NAME "${CPACK_RPM_PACKAGE_NAME}-${VERSION}-${RPM}-${CMAKE_SYSTEM_PROCESSOR}")
+IF(CMAKE_VERSION VERSION_LESS "3.6.0")
+  SET(CPACK_PACKAGE_FILE_NAME "${CPACK_RPM_PACKAGE_NAME}-${VERSION}-${RPM}-${CMAKE_SYSTEM_PROCESSOR}")
+ELSE()
+  SET(CPACK_RPM_FILE_NAME "RPM-DEFAULT")
+ENDIF()
 
 SET(CPACK_RPM_PACKAGE_RELEASE "1%{?dist}")
 SET(CPACK_RPM_PACKAGE_LICENSE "GPLv2")