Fix for CONC-99: memory corruption   In case a connection fails and vio was already created the socket needs to be closed   only via vio_close. A 2nd close may lead to corruption in a threaded evironment in case   the handle was opened by a nother thread.
Fix for CONC-99: memory corruption
  In case a connection fails and vio was already created the socket needs to be closed
  only via vio_close. A 2nd close may lead to corruption in a threaded evironment in case
  the handle was opened by a nother thread.

grubba/mariadb-connector-c,ottok/mariadb-connector-c,ottok/mariadb-connector-c,ericherman/mariadb-connector-c,grubba/mariadb-connector-c,ottok/mariadb-connector-c,MariaDB/mariadb-connector-c,ericherman/mariadb-connector-c,MariaDB/mariadb-connector-c,MariaDB/mariadb-connector-c,ericherman/mariadb-connector-c,grubba/mariadb-connector-c