MBSResolver: improve efficiency of querying latest version

Only get 5 results at a time, and if we see that we're already
retrieving an old versions, stop requesting more pages.

module_build_service/resolver/MBSResolver.py

@@ -66,7 +66,7 @@ class MBSResolver(KojiResolver):
         """
         query = self._query_from_nsvc(name, stream, version, context, states)
         query["page"] = 1
-        query["per_page"] = 10
+        query["per_page"] = 5
         query.update(kwargs)
         modules = []
 
@@ -81,6 +81,11 @@ class MBSResolver(KojiResolver):
             if not data["meta"]["next"]:
                 break
 
+            if version is None and "stream_version_lte" not in kwargs:
+                # Stop querying when we've gotten a different version
+                if modules_per_page[-1]["version"] != modules[0]["version"]:
+                    break
+
             query["page"] += 1
 
         # Error handling