Fix flake8 errors

Change-Id: Idb1c1fbe9484b118ec6fe20b7176e173c83694a1

monasca_agent/collector/checks/collector.py

@@ -267,7 +267,7 @@ class Collector(util.Dimensions):
         if len(self.collection_results) >= self.pool_size:
             self.pool_full_count += 1
             if (self.pool_full_count > self.pool_full_max_retries):
-                log.error('Thread Pool full and %d plugins still running for ' +
+                log.error('Thread Pool full and %d plugins still running for '
                           '%d collection cycles, exiting' %
                           (len(self.collection_results), self.pool_full_count))
                 os._exit(1)

monasca_agent/collector/checks_d/apache.py

@@ -123,7 +123,8 @@ class Apache(checks.AgentCheck):
                 self.check(instance)
             else:
                 return services_checks.Status.DOWN,
-                "%s is DOWN, error: No metrics available.".format(service_check_name)
+                "{} is DOWN, error: No metrics available.".format(
+                    service_check_name)
         else:
             log.debug("Collected {0} metrics for {1} Apache Web Server".format(apache_host,
                                                                                metric_count))

monasca_agent/collector/checks_d/ceph.py

@@ -407,8 +407,8 @@ class Ceph(checks.AgentCheck):
         # In Luminous the format of output parsed here changed slightly.
         # Check for both known variations.
         ceph_status_plain = ceph_status_plain.split('\n')
-        for l in ceph_status_plain:
-            line = l.strip(' ')
+        for raw_line in ceph_status_plain:
+            line = raw_line.strip(' ')
             if line.startswith('recovery io') or line.startswith('recovery:'):
                 metrics.update(self._get_recovery_io(line))
             elif line.startswith('client io') or line.startswith('client:'):

monasca_agent/collector/checks_d/tcp_check.py

@@ -66,7 +66,8 @@ class TCPCheck(ServicesCheck):
         addr, port, socket_type, timeout, response_time = self._load_conf(instance)
         dimensions = self._set_dimensions(None, instance)
         if instance.get('host'):
-            dimensions.update({'url': '%s:%s'.format(instance.get('host'), port)})
+            dimensions.update({'url': '{}:{}'.format(instance.get('host'),
+                                                     port)})
         start = time.time()
         try:
             self.log.debug("Connecting to %s %s" % (addr, port))