DataSourceOpenNebula:parse_shell_config skip 'SECONDS' var if seen

SECONDS is a special variable in bash, it gets set to the time the
shell has been alive.  This would cause us to fail randomly (if the
process happened to take more than 1 second, then SECONDS would
be defined).

cloudinit/sources/DataSourceOpenNebula.py

@@ -323,7 +323,7 @@ def parse_shell_config(content, keylist=None, bash=None, asuser=None,
     (output, _error) = util.subp(cmd, data=bcmd)
 
     # exclude vars in bash that change on their own or that we used
-    excluded = ("RANDOM", "LINENO", "_", "__v")
+    excluded = ("RANDOM", "LINENO", "SECONDS", "_", "__v")
     preset = {}
     ret = {}
     target = None

tests/unittests/test_datasource/test_opennebula.py

@@ -258,6 +258,14 @@ iface eth0 inet static
 ''')
 
 
+class TestParseShellConfig(MockerTestCase):
+    def test_no_seconds(self):
+        cfg = '\n'.join(["foo=bar", "SECONDS=2", "xx=foo"])
+        # we could test 'sleep 2', but that would make the test run slower.
+        ret = ds.parse_shell_config(cfg);
+        self.assertEqual(ret, {"foo": "bar", "xx": "foo"})
+
+
 def populate_context_dir(path, variables):
     data = "# Context variables generated by OpenNebula\n"
     for (k, v) in variables.iteritems():