Preserve the CLIENT_REMEMBER_OPTIONS flag for compressed connections

Summary:
I heard someone recently state that we turn on compression for the
slaves' connections to their masters. This reminded me that there is
a bug in the bit math for turning on this setting which caused problems
in my past job. Fix it here too.

Specifically, keep the CLIENT_REMEMBER_OPTIONS bit set in the flags for
the IO thread's connection so that on failure connecting to the master
mysql_real_connect does not call mysql_close_free_options and stomp the
connection timeout setting.

Test Plan: mtr

Reviewers: steaphan

Reviewed By: steaphan

sql/slave.cc

@@ -4222,7 +4222,7 @@ static int connect_to_master(THD* thd, MYSQL* mysql, Master_info* mi,
 #endif
   ulong client_flag= CLIENT_REMEMBER_OPTIONS;
   if (opt_slave_compressed_protocol)
-    client_flag=CLIENT_COMPRESS;                /* We will use compression */
+    client_flag |= CLIENT_COMPRESS;             /* We will use compression */
 
   mysql_options(mysql, MYSQL_OPT_CONNECT_TIMEOUT, (char *) &slave_net_timeout);
   mysql_options(mysql, MYSQL_OPT_READ_TIMEOUT, (char *) &slave_net_timeout);