Fix Python3.4 compability

Add Zuul unit test job

Change-Id: I2dbcd27db0d1791c06c212b07f23d1f26e1fd5ad
Closes-Bug: #1814218

.zuul.yaml

@@ -1,3 +1,3 @@
 - project:
     templates:
-      - python-charm-interface-jobs
+      - python35-charm-jobs

common.py

@@ -339,7 +339,11 @@ class CRM(dict):
         http://crmsh.github.io/man/#cmdhelp_configure_delete
         """
         if resource not in self['delete_resources']:
-            self['delete_resources'] = (*self['delete_resources'], resource)
+            # NOTE(fnordahl): this unpleasant piece of code is regrettably
+            # necessary for Python3.4 (and trusty) compability see LP: #1814218
+            # and LP: #1813982
+            self['delete_resources'] = tuple(
+                self['delete_resources'] or ()) + (resource,)
             self.remove_deleted_resources()
 
     def init_services(self, *resources):

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = pep8,py35
+envlist = pep8,py34,py35,py36
 skipsdist = True
 skip_missing_interpreters = True
 
@@ -10,6 +10,11 @@ install_command =
   pip install {opts} {packages}
 commands = ostestr {posargs}
 
+[testenv:py34]
+basepython = python3.4
+deps = -r{toxinidir}/test-requirements.txt
+commands = ostestr {posargs}
+
 [testenv:py35]
 basepython = python3.5
 deps = -r{toxinidir}/test-requirements.txt