fix the escape sequence.

src/parser/test_memory_leaks.sh

@@ -30,7 +30,7 @@ int main(int argc, char **argv) {
   q = parse_query("select value from cpu.idle where value > 90 and (time > now() - 1d or value > 80) and time < now() - 1w last 10;");
   close_query(&q);
 
-  q = parse_query("select email from users.events where email ~= /gmail\\.com/i and time>now()-2d;");
+  q = parse_query("select email from users.events where email ~= /gmail\\\\.com/i and time>now()-2d;");
   close_query(&q);
 
   return 0;