just warn if Heapster is not deployed (Minikube is missing it)

kube_ops_view/utils.py

@@ -0,0 +1,14 @@
+import requests.exceptions
+
+
+def get_short_error_message(e: Exception):
+    '''Generate a reasonable short message why the HTTP request failed'''
+
+    if isinstance(e, requests.exceptions.RequestException) and e.response is not None:
+        # e.g. "401 Unauthorized"
+        return '{} {}'.format(e.response.status_code, e.response.reason)
+    elif isinstance(e, requests.exceptions.ConnectionError):
+        # e.g. "ConnectionError" or "ConnectTimeout"
+        return e.__class__.__name__
+    else:
+        return str(e)