tests/test-install.t

largefiles: drop a redundant check for patterns when removing without --after

This is in the way of passing a matcher to removelargefiles().  This method is
called in exactly two places- first in overrides.addremove() (but only if the
pattern list passed to it is not empty), and second in the commands.remove()
override.  But since the latter calls commands.remove() first, which also does
this check, it isn't needed here.

hg debuginstall
  $ hg debuginstall
  checking encoding (ascii)...
  checking Python executable (*) (glob)
  checking Python version (2.*) (glob)
  checking Python lib (*lib*)... (glob)
  checking installed modules (*mercurial)... (glob)
  checking templates (*mercurial?templates)... (glob)
  checking commit editor...
  checking username...
  no problems detected

hg debuginstall with no username
  $ HGUSER= hg debuginstall
  checking encoding (ascii)...
  checking Python executable (*) (glob)
  checking Python version (2.*) (glob)
  checking Python lib (*lib*)... (glob)
  checking installed modules (*mercurial)... (glob)
  checking templates (*mercurial?templates)... (glob)
  checking commit editor...
  checking username...
   no username supplied
   (specify a username in your configuration file)
  1 problems detected, please check your install!
  [1]