Added shll envirunment for subprocess

ee/core/shellexec.py

@@ -18,7 +18,7 @@ class EEShellExec():
                 Log.debug(self, "Running command: {0}".format(command))
             args = shlex.split(command)
             with subprocess.Popen(args, stdout=subprocess.PIPE,
-                                  stderr=subprocess.PIPE) as proc:
+                                  stderr=subprocess.PIPE, shell=True) as proc:
                 (cmd_stdout_bytes, cmd_stderr_bytes) = proc.communicate()
                 (cmd_stdout, cmd_stderr) = (cmd_stdout_bytes.decode('utf-8',
                                             "replace"),