The test rpl_blackhole was executed even when

there were no blackhole installed. This patch
adds a check for that.

mysql-test/suite/rpl/t/rpl_blackhole.test:
  Adding include of have_blackhole.

mysql-test/suite/rpl/t/rpl_blackhole.test

---source include/master-slave.inc
-
 # PURPOSE. Test that blackhole works with replication in all three
 # modes: STATEMENT, MIXED, and ROW.
 #
@@ -17,6 +15,9 @@
 # primary key lookup), and index/key with multiple matches (forcing an
 # index search).
 
+source include/master-slave.inc;
+source include/have_blackhole.inc;
+
 # We start with no primary key
 CREATE TABLE t1 (a INT, b INT, c INT);
 CREATE TABLE t2 (a INT, b INT, c INT);