Remove extra container check

This code is only ever called from functions which have already
checked if the target is a container, so the check is duplicate.

Change-Id: If63269719881c04804d6d17f6134cc67ab0bb9a7

plugins/connection/ssh.py

@@ -437,9 +437,6 @@ class Connection(SSH.Connection):
         so that a container lookup is not required on a subsequent
         command within the same task.
         """
-        if not self.is_container:
-          return 1, ''
-
         pid_path = """/proc/%s"""
         if not subdir:
             subdir = 'root'