ms_driver: Rename method to hopefully be more clear

This is finding min/max in a dataset. Call it like this and update
the caller.

Change-Id: Ic7f5cd34639f897e460ca1edcb4f9b6df44683e9
diff --git a/src/osmo_ms_driver/location_update_test.py b/src/osmo_ms_driver/location_update_test.py
index 90e405e..8500607 100644
--- a/src/osmo_ms_driver/location_update_test.py
+++ b/src/osmo_ms_driver/location_update_test.py
@@ -198,7 +198,7 @@
     def all_completed(self):
         return self._outstanding == 0
 
-    def results_min_max(self, results):
+    def find_min_max(self, results):
         min_value = max_value = None
         for result in results:
             if min_value is None or result.lu_delay() < min_value:
@@ -209,7 +209,7 @@
 
     def print_stats(self):
         all_completed = self.all_completed()
-        min_value, max_value = self.results_min_max(filter(lambda x: x.has_lu_time(), self._results.values()))
+        min_value, max_value = self.find_min_max(filter(lambda x: x.has_lu_time(), self._results.values()))
 
         self.log("Tests done", all_completed=all_completed,
                     min=min_value, max=max_value)