Add function 'vio_end' that will cleanup resources allocated by vio and the components it uses.


include/violite.h:
  Import patch warnings.patch
libmysql/libmysql.c:
  Import patch warnings.patch
sql/mysqld.cc:
  Import patch warnings.patch
vio/test-ssl.c:
  Import patch warnings.patch
vio/test-sslclient.c:
  Import patch warnings.patch
vio/test-sslserver.c:
  Import patch warnings.patch
vio/vio.c:
  Import patch warnings.patch
vio/viosslfactories.c:
  Import patch warnings.patch