qapi/gen.py: delint with pylint

'fp' and 'fd' are self-evident in context, add them to the list of OK
names.

_top and _bottom also need to stay standard methods because some users
override the method and need to use `self`. Tell pylint to shush.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Cleber Rosa <crosa@redhat.com>
Message-Id: <20201009161558.107041-32-jsnow@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>

scripts/qapi/gen.py

@@ -51,9 +51,11 @@ class QAPIGen:
         return self._top() + self._preamble + self._body + self._bottom()
 
     def _top(self) -> str:
+        # pylint: disable=no-self-use
         return ''
 
     def _bottom(self) -> str:
+        # pylint: disable=no-self-use
         return ''
 
     def write(self, output_dir: str) -> None:

scripts/qapi/pylintrc

@@ -4,7 +4,6 @@
 # The regex matches against base names, not paths.
 ignore-patterns=error.py,
                 expr.py,
-                gen.py,
                 parser.py,
                 schema.py,
                 types.py,
@@ -45,7 +44,9 @@ good-names=i,
            k,
            ex,
            Run,
-           _
+           _,
+           fp,  # fp = open(...)
+           fd,  # fd = os.open(...)
 
 [VARIABLES]