tests/test-username-newline.t

infinitepush: use the new function to determine push destination

Since 066b8d8f75b8, the push command accept multiple destination. `infinitepush`
was not aware of that. We now use the new `urlutil.get_push_paths` function to
determine the push destination, fixing the issue. This will also make future
evolution of that logic transparent for infinitepush

We still disallow push to multiple destinations if infinite push is enabled
because I don't know what this means for infinite push. However user will now
get a clear error message instead of a crash.

Differential Revision: https://phab.mercurial-scm.org/D10379

  $ hg init
  $ touch a

  $ unset HGUSER
  $ echo "[ui]" >> .hg/hgrc
  $ echo "username= foo" >> .hg/hgrc
  $ echo "          bar1" >> .hg/hgrc

  $ hg ci -Am m
  adding a
  abort: username 'foo\nbar1' contains a newline
  
  [255]
  $ rm .hg/hgrc

  $ HGUSER=`(echo foo; echo bar2)` hg ci -Am m
  adding a
  abort: username 'foo\nbar2' contains a newline
  
  [255]
  $ hg ci -Am m -u "`(echo foo; echo bar3)`"
  adding a
  transaction abort!
  rollback completed
  abort: username 'foo\nbar3' contains a newline
  [50]