fix(LinstorSR): explicit errors when database path is fetched

Author: Wescoeur

drivers/LinstorSR.py

@@ -766,15 +766,15 @@ def scan(self, uuid):
         # is started without a shared and mounted /var/lib/linstor path.
         try:
             self._linstor.get_database_path()
-        except Exception:
+        except Exception as e:
             # Failed to get database path, ensure we don't have
             # VDIs in the XAPI database...
             if self.session.xenapi.SR.get_VDIs(
                 self.session.xenapi.SR.get_by_uuid(self.uuid)
             ):
                 raise xs_errors.XenError(
                     'SRUnavailable',
-                    opterr='Database is not mounted'
+                    opterr='Database is not mounted or node name is invalid ({})'.format(e)
                 )
 
         # Update the database before the restart of the GC to avoid

drivers/linstorvolumemanager.py

@@ -2648,7 +2648,7 @@ def _request_database_path(cls, lin, activate=False):
             )
         except Exception as e:
             raise LinstorVolumeManagerError(
-                'Unable to get resources during database creation: {}'
+                'Unable to fetch database resource: {}'
                 .format(e)
             )