Because of argument order to assert, in case of fail, we'll get message
like:

... obtained string = "uid=100(test) gid=101(test)\n"
... expected string = "uid=100(test) gid=101(test) groups=101(test)\n"

But obtained string should be second one, not the first one. And
expected string should be first. Here's sample output from test above:

... Output: before restart 'uid=100(test) gid=101(test)
', after restart 'uid=100(test) gid=101(test) groups=101(test)

It's confusing, because expected order of strings in assertion is
reversed. What goes before restart - should be "expected string" and
what goes after - should be "obtained string".

Signed-off-by: Vitaly Ostrosablin <vostrosablin@virtuozzo.com>