Fix incorrect error handling in ipapython/graph.py

fix: correction in exception type for remove_edge

the previous code raises the KeyError but the list.remove() actually raises ValueError so the Actual problem was not getting resolved.

Fixes:https://pagure.io/freeipa/issue/9876

signed-off-by: Sami Shaikh 1694samishaikh@gmail.com
Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>
Reviewed-By: Alexander Bokovoy <abbra@users.noreply.github.com>

ipapython/graph.py

@@ -34,7 +34,7 @@ class Graph:
     def remove_edge(self, tail, head):
         try:
             self.edges.remove((tail, head))
-        except KeyError:
+        except ValueError:
             raise ValueError(
                 "graph does not contain edge: ({0}, {1})".format(tail, head)
             )