Catch illegal boolean values in hgrc nicely.
With hg 0.9.3 the section and parameter name wasn't printed,
with hg 0.9.4 there was a traceback for ValueError.
adding base
abort: cannot delete applied patch c
Now at: b
a
b
a
b
series
status
Now at: a
a
b
series
status
1 [mq]: a
0 base
abort: cannot delete revision 3 above applied patches
f
4 [mq]: f
3 [mq]: e
2 [mq]: d
1 [mq]: a
0 base