Free evdns_base->req_heads on evdns_base_free

It looks like when we moved from one big inflight-requests list to an
n-heads structure, we didn't make evdns_base_free() free the array of
heads.  This patch should fix that.

Found with valgrind

1 files changed, 2 insertions, 0 deletions

diff --git a/evdns.c b/evdns.c
index e9cbec76..88d6fa37 100644
--- a/evdns.c
+++ b/evdns.c
@@ -3775,6 +3775,8 @@ evdns_base_free_and_unlock(struct evdns_base *base, int fail_requests)
 		}
 	}
 
+	mm_free(base->req_heads);
+
 	EVDNS_UNLOCK(base);
 	EVTHREAD_FREE_LOCK(base->lock, EVTHREAD_LOCKTYPE_RECURSIVE);