convert: disable current --filemap support
The --filemap support in hg convert doesn't handle merges correctly.
(And after 33015dac5df5 I managed to break it even for simple cases
where we don't want the first revision.)
#!/bin/sh
# a test for issue586
hg init a
cd a
echo a > a
hg ci -Ama
hg init ../b
cd ../b
echo b > b
hg ci -Amb
hg pull -f ../a
hg merge
hg rm -f a
hg ci -Amc
hg st -A