Handle ECONNREFUSED exception in SolidFire driver.

The SolidFire driver wasn't handling connection exceptions
during init (capacity updates from scheduler).

This patch add a try/except wrap around the two places
that this is called and logs and error rather than crashing
cinder-volume service.

Fixes bug: 1195910

Change-Id: I30347cc0973bbf9dbc30ea02e204560095fc75b4
(cherry picked from commit d596bfe)

cinder/volume/drivers/solidfire.py

@@ -77,7 +77,12 @@ class SolidFire(SanISCSIDriver):
     def __init__(self, *args, **kwargs):
             super(SolidFire, self).__init__(*args, **kwargs)
             self.configuration.append_config_values(sf_opts)
-            self._update_cluster_status()
+            try:
+                self._update_cluster_status()
+            except Exception as ex:
+                LOG.error(_("Update SolidFire Cluster stats failed: %s"),
+                          ex.strerror)
+                pass
 
     def _issue_api_request(self, method_name, params):
         """All API requests to SolidFire device go through this method.
@@ -555,7 +560,12 @@ def get_volume_stats(self, refresh=False):
         data
         """
         if refresh:
-            self._update_cluster_status()
+            try:
+                self._update_cluster_status()
+            except Exception as ex:
+                LOG.error(_("Update SolidFire Cluster stats failed: %s"),
+                          ex.strerror)
+                pass
 
         return self.cluster_stats