make my_vsnprintf() work with oversized strings

fixed replication bug - flush_master_info() needs to be called every time we read an 
    event from master

this is will not be pushed yet

mysys/my_vsnprintf.c

@@ -39,7 +39,7 @@ int my_vsnprintf(char *to, size_t n, const char* fmt, va_list ap)
       *to++= *fmt;			/* Copy ordinary char */
       continue;
     }
-    /* Skipp if max size is used (to be compatible with printf) */
+    /* Skip if max size is used (to be compatible with printf) */
     fmt++;
     while (isdigit(*fmt) || *fmt == '.' || *fmt == '-')
       fmt++;
@@ -48,14 +48,13 @@ int my_vsnprintf(char *to, size_t n, const char* fmt, va_list ap)
     if (*fmt == 's')				/* String parameter */
     {
       reg2 char	*par = va_arg(ap, char *);
-      uint plen;
+      uint plen,left_len = (uint)(end-to);
       if (!par) par = (char*)"(null)";
       plen = (uint) strlen(par);
-      if ((uint) (end-to) > plen)	/* Replace if possible */
-      {
-	to=strmov(to,par);
-	continue;
-      }
+      if (left_len <= plen)
+	plen = left_len - 1;
+      to=strmov(to,par);
+      continue;
     }
     else if (*fmt == 'd' || *fmt == 'u')	/* Integer parameter */
     {

sql/log.cc

@@ -237,7 +237,8 @@ void MYSQL_LOG::open(const char *log_name, enum_log_type log_type_arg,
     /*
       Explanation of the boolean black magic:
       if we are supposed to write magic number try write
-      clean up if failed
+      clean 
+up if failed
       then if index_file has not been previously opened, try to open it
       clean up if failed
     */

sql/slave.cc

@@ -1762,6 +1762,7 @@ reconnect done to recover from failed read");
 from master");
 	goto err;
       }
+      flush_master_info(mi);
       // TODO: check debugging abort code
 #ifndef DBUG_OFF
       if (abort_slave_event_count && !--events_till_abort)