Modify log message in debug_ssh

In debug_ssh, if the raised exception is not instance of
tempest.lib.exceptions.SSHTimeout, then it maybe the instance
of exceptions.TimeoutException or exceptions.SSHExecCommandFailed,
which both indicate command executing error, but the log message
will display "Initializing SSH connection to %(ip)s failed." which
is not accurate. This is to change the log info to
"Executing command on %(ip)s failed."

Change-Id: I8f081e856231a609a32621240f3c6c22aa74c74e

tempest/lib/common/utils/linux/remote_client.py

@@ -31,7 +31,7 @@ def wrapper(self, *args, **kwargs):
         except Exception as e:
             caller = test_utils.find_test_caller() or "not found"
             if not isinstance(e, tempest.lib.exceptions.SSHTimeout):
-                message = ('Initializing SSH connection to %(ip)s failed. '
+                message = ('Executing command on %(ip)s failed. '
                            'Error: %(error)s' % {'ip': self.ip_address,
                                                  'error': e})
                 message = '(%s) %s' % (caller, message)