largefiles: remove unnecessary clearing of status fields
At the end of lfilesrepo.status(), we clear the lists of unknown,
ignored and clean files, depending on the values of 'listunknown'
etc. The lists originate from other calls to status(), and it is only
'clean' that may get updated after the calls. Let's remove the need to
clear any of the lists by explicitly only adding to 'clean' when
'listclean' is true.
os = <unloaded module 'os'>
os.system = <built-in function system>
os = <module 'os' from '?'>
util = <unloaded module 'util'>
util.system = <function system at 0x?>
util = <module 'mercurial.util' from '?'>
util.system = <function system at 0x?>
fred = <unloaded module 're'>
re = <unloaded module 'sys'>
fred = <unloaded module 're'>
fred.sub = <function sub at 0x?>
fred = <proxied module 're'>
re = <unloaded module 'sys'>
re.stderr = <open file '<whatever>', mode 'w' at 0x?>
re = <proxied module 'sys'>
node = <module 'mercurial.node' from '?'>