conf: Don't complicate find loop

Signed-off-by: NMartin Kletzander <mkletzan@redhat.com>

src/conf/domain_conf.c

@@ -14898,12 +14898,9 @@ virDomainShmemDefFind(virDomainDefPtr def,
 
     for (i = 0; i < def->nshmems; i++) {
         if (virDomainShmemDefEquals(shmem, def->shmems[i]))
-            break;
+            return i;
     }
 
-    if (i < def->nshmems)
-        return i;
-
     return -1;
 }