[PATCH] Wrong macro expansion in Query_cache::send_result_to_client()

Query_cache::send_result_to_client() has a statement here https://github.com/MariaDB/server/blob/10.1/sql/sql_cache.cc#L2141 that looks like the following:

thd->query_plan_flags= (thd->query_plan_flags & ~QPLAN_QC_NO) | QPLAN_QC;

Given that QPLAN_QC_NO is defined as 1 << 6 (without parenthesis) in https://github.com/MariaDB/server/blob/10.1/sql/log_slow.h, the expression expands into something that is apparently not wanted.

All macro definitions in sql/log_slow.h should be put in parenthesis.