test-relink: remove unnecessary ui.username setting

tests/test-relink.t

@@ -20,8 +20,6 b' create source repository'
 
   $ hg init repo
   $ cd repo
-  $ echo '[ui]' > .hg/hgrc
-  $ echo 'username= A. Foo <[e-mail]>' >> .hg/hgrc
   $ echo a > a
   $ echo b > b
   $ hg ci -Am addfile
@@ -47,8 +45,6 b' clone and pull to break links'
   updating to branch default
   2 files updated, 0 files merged, 0 files removed, 0 files unresolved
   $ cd clone
-  $ echo '[ui]' >> .hg/hgrc
-  $ echo 'username= A. Baz <[e-mail]>' >> .hg/hgrc
   $ hg pull -q
   $ echo b >> b
   $ hg ci -m changeb