Jun Wu <quark@fb.com> [Tue, 09 May 2017 19:23:28 -0700] rev 32278
filectx: make flags a property cache
Make basefilectx._flags a property cache, so basefilectx.flags() could be
reasonably reused. This avoids code duplication between memfilectx and a
class added in a later patch.
commandserver: move printbanner logic to bindsocket
bindsocket now handles listen automatically. "printbanner" seems to be just
a part of "bindsocket". This simplifies the interface a bit.