util/uri: do not check argument of uri_free()

uri_free() checks if its argument is NULL in uri_clean() and g_free().
There is no need to check the argument before the call.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Message-Id: <20210629063602.4239-1-xypron.glpk@gmx.de>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Richard W.M. Jones <rjones@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>