bundle2: equate 'UN' with no compression
An upcoming patch will change the "alg" argument passed to this
function from None to "UN" when no compression is wanted.
The existing implementation of bundle2 does not set a "Compression"
parameter if no compression is used. In theory, setting
"Compression=UN" should work. But I haven't audited the code to see if
all client versions supporting bundle2 will accept this.
Rather than take the risk, avoid the BC breakage and treat "UN"
the same as None.
#require docutils gettext
$ $TESTDIR/check-gendoc sv
checking for parse errors