Fixed linting issues

Newer versions of flake8 identify these valid violations.
N802 added as skip because the entire library uses camelcase.

Change-Id: Ia687b05bb8d0590eb30a970a710a2639548dbc60

gerritlib/gerrit.py

@@ -130,8 +130,8 @@ class GerritWatcher(threading.Thread):
         self.state = IDLE
 
     def _read(self, fd):
-        l = fd.readline()
-        data = json.loads(l)
+        line = fd.readline()
+        data = json.loads(line)
         self.log.debug("Received data from Gerrit event stream: \n%s" %
                        pprint.pformat(data))
         self.gerrit.addEvent(data)
@@ -316,7 +316,7 @@ class Gerrit(object):
         else:
             cmd = 'gerrit ls-groups'
         # ensure group names with spaces are escaped and quoted
-        group = "\"%s\"" % group.replace(' ', '\ ')
+        group = "\"%s\"" % group.replace(' ', r'\ ')
         out, err = self._ssh(' '.join([cmd, '-q', group]))
         return list(filter(None, out.split('\n')))
 

tox.ini

@@ -24,4 +24,9 @@ commands = {posargs}
 
 [flake8]
 show-source = True
+# These are ignored intentionally in infra projects;
+# please don't submit patches that solely correct them or enable them.
+ignore =
+    E124,E125,E129,E252,E402,E741,H,W503,W504
+    N802  # N802 function name {} should be lowercase
 exclude = .venv,.tox,dist,doc,build,*.egg