Wait for first pull to be completed before doing verify.

tests/test-pull-pull-corruption2

@@ -1,24 +1,25 b''
 #!/bin/sh
 #
 # Corrupt an hg repo with two pulls.
 #
 
 # create one repo with a long history
 hg init source1
 cd source1
 touch foo
 hg add foo
 for i in 1 2 3 4 5 6 7 8 9 10; do
     echo $i >> foo
     hg ci -m $i
 done
 cd ..
 
 # create a third repo to pull both other repos into it
 hg init version2
 hg -R version2 pull source1 &
 sleep 1
 
 hg clone --pull -U version2 corrupted
+wait
 hg -R corrupted verify
 hg -R version2 verify