Fix new pylint errors

Fix the following new errors detected by pylint 3.2.0.
 - possibly-used-before-assignment
 - used-before-assignment
 - useless-return

Change-Id: Ibfa282e7311a06ed69797cb9969aa66459372d79

octavia/amphorae/backends/agent/api_server/keepalived.py

@@ -64,6 +64,7 @@ class Keepalived:
 
         file_path = util.keepalived_init_path(init_system)
 
+        init_enable_cmd = None
         if init_system == consts.INIT_SYSTEMD:
             template = SYSTEMD_TEMPLATE
             init_enable_cmd = "systemctl enable octavia-keepalived"
@@ -117,7 +118,7 @@ class Keepalived:
         util.vrrp_check_script_update(None, consts.AMP_ACTION_START)
 
         # Make sure the new service is enabled on boot
-        if init_system != consts.INIT_UPSTART:
+        if init_enable_cmd is not None:
             try:
                 subprocess.check_output(init_enable_cmd.split(),
                                         stderr=subprocess.STDOUT)

octavia/amphorae/backends/agent/api_server/keepalivedlvs.py

@@ -304,12 +304,9 @@ class KeepalivedLvs(lvs_listener_base.LvsListenerApiServerBase):
         if init_system == consts.INIT_SYSTEMD:
             util.run_systemctl_command(
                 consts.DISABLE, f"octavia-keepalivedlvs-{listener_id}")
+
         elif init_system == consts.INIT_SYSVINIT:
             init_disable_cmd = f"insserv -r {init_path}"
-        elif init_system != consts.INIT_UPSTART:
-            raise util.UnknownInitError()
-
-        if init_system == consts.INIT_SYSVINIT:
             try:
                 subprocess.check_output(init_disable_cmd.split(),
                                         stderr=subprocess.STDOUT)
@@ -323,6 +320,9 @@ class KeepalivedLvs(lvs_listener_base.LvsListenerApiServerBase):
                         "{} service".format(listener_id)),
                     'details': e.output}, status=500)
 
+        elif init_system != consts.INIT_UPSTART:
+            raise util.UnknownInitError()
+
         # delete init script ,config file and log file for that listener
         if os.path.exists(init_path):
             os.remove(init_path)

octavia/amphorae/backends/agent/api_server/loadbalancer.py

@@ -396,12 +396,9 @@ class Loadbalancer:
             util.run_systemctl_command(
                 consts.DISABLE, "haproxy-{lb_id}".format(
                     lb_id=lb_id))
+
         elif init_system == consts.INIT_SYSVINIT:
             init_disable_cmd = f"insserv -r {init_path}"
-        elif init_system != consts.INIT_UPSTART:
-            raise util.UnknownInitError()
-
-        if init_system == consts.INIT_SYSVINIT:
             try:
                 subprocess.check_output(init_disable_cmd.split(),
                                         stderr=subprocess.STDOUT)
@@ -413,6 +410,9 @@ class Loadbalancer:
                     'message': "Error disabling haproxy-{} service".format(
                         lb_id), 'details': e.output}, status=500)
 
+        elif init_system != consts.INIT_UPSTART:
+            raise util.UnknownInitError()
+
         # delete the directory + init script for that listener
         shutil.rmtree(util.haproxy_dir(lb_id))
         if os.path.exists(init_path):

octavia/common/tls_utils/cert_parser.py

@@ -193,6 +193,7 @@ def _read_pem_blocks(data):
     state = stSpam
     if isinstance(data, bytes):
         data = data.decode('utf-8')
+    certLines = []
     for certLine in data.replace('\r', '').split('\n'):
         if not certLine:
             continue

octavia/controller/worker/v2/tasks/compute_tasks.py

@@ -342,8 +342,6 @@ class NovaServerGroupDelete(BaseComputeTask):
     def execute(self, server_group_id):
         if server_group_id is not None:
             self.compute.delete_server_group(server_group_id)
-        else:
-            return
 
 
 class AttachPort(BaseComputeTask):