Fix dagman tests that have race conditions #3359

For some reason, the shadows on FreeBSD7 machine in Batlab are very slow
in updating the Userlog.  This causes spurious failures to be reported
in the test suite. To solve these problems, I did the following:

1. Introduce a sleep in job_dagman_fullremove
2. Add sleep to job_dagman_halt-A
Partial revert of "Fix dagman tests that have race conditions #3359"

Revert the part where a sleep was added to job_dagman_halt-A.  I had no
effect.