Remove stale comments that restated the obvious

Drop NullLock rationale comment (referenced removed library),
consoleserver greenthread spawn comment, and update syncfiles
CalledProcessError workaround comment.

confluent_server/confluent/consoleserver.py

@@ -462,7 +462,6 @@ class ConsoleHandler(object):
             self._attribwatcher = None
 
     async def get_console_output(self, data):
-        # Return control as soon as possible to the console object
         await self._handle_console_output(data)
 
     async def attachsession(self, session):

confluent_server/confluent/plugins/hardwaremanagement/ipmi.py

@@ -98,9 +98,6 @@ def get_pci_text_from_ids(subdevice, subvendor, device, vendor):
     return vendorstr, devstr
 
 
-# Since we are single-threaded via asyncio, the operations being protected
-# by RLocks are not actually dangerously multiplexed, so we can replace
-# with a null context manager
 class NullLock(object):
 
     def donothing(self, *args, **kwargs):

confluent_server/confluent/syncfiles.py

@@ -199,8 +199,8 @@ async def sync_list_to_node(sl, node, suffixes, peerip=None):
             'rsync', '-rvLD', targdir + '/', 'root@[{}]:/'.format(targip))
     except Exception as e:
         if 'CalledProcessError' not in repr(e):
-            # CalledProcessError can't be caught normally in some contexts,
-            # so check via repr as a workaround
+            # CalledProcessError can't be caught normally through
+            # asyncio subprocess, so check via repr as a workaround
             raise
         unreadablefiles = []
         for root, dirnames, filenames in os.walk(targdir):