CamelSession: Avoid camel_session_lock/unlock().
CamelSession: Avoid camel_session_lock/unlock().

Use an internal mutex to guard the services hash table.

Distrotech/evolution-data-server,tintou/evolution-data-server,Distrotech/evolution-data-server,tintou/evolution-data-server,Distrotech/evolution-data-server,matzipan/evolution-data-server,Distrotech/evolution-data-server,tintou/evolution-data-server,tintou/evolution-data-server,matzipan/evolution-data-server,matzipan/evolution-data-server,matzipan/evolution-data-server,Distrotech/evolution-data-server,matzipan/evolution-data-server