mq: test qtop with holes in the patch sequence.

tests/test-mq-guards

@@ -76,6 +76,10 b' hg qpop -a'
 hg qselect 2
 echo % should push b.patch
 hg qpush
+hg qpush -a
+# Used to be an issue with holes in the patch sequence
+# So, put one hole on the base and ask for topmost patch.
+hg qtop
 hg qpop -a
 
 hg qselect 1 2

tests/test-mq-guards.out

@@ -46,6 +46,9 b' Patch queue now empty'
 % should push b.patch
 applying b.patch
 Now at: b.patch
+applying c.patch
+Now at: c.patch
+c.patch
 Patch queue now empty
 number of unguarded, unapplied patches has changed from 2 to 3
 % should push a.patch, b.patch