Changed skip into error (#3698)

Problem:
if common fails target map/char/login will be disabled.

Solution:
if common fails stop cmake execution and throw an error, this will avoid building only mapcache and common_base.

src/common/CMakeLists.txt

@@ -188,6 +188,5 @@ set( HAVE_common ON  CACHE INTERNAL "" )
 set( TARGET_LIST ${TARGET_LIST} common  CACHE INTERNAL "" )
 message( STATUS "Creating target common - done" )
 else()
-message( STATUS "Skipping target common (requires common_base and MYSQL)" )
-unset( HAVE_common CACHE )
+message( FATAL_ERROR "Stopping target common (requires common_base and MYSQL)" )
 endif()