[Nmh-workers] Patch: backup prefix assumption corrections

[belg4mit]

Attached is a patch to fix the previously reported test errors that
had hardcoded , en lieu of `mhparam sbackup` I commented out the
existing test in test-mhparam, but could not figure out what environment
variable might contain the configured value to incorporate it into
the same heredoc test as everything else. However, since it is used
in so many other test via the backtick execution, it's arguably redundant.

Also, although I did not encounter this when building from the RC1
tarball, I started getting this error using my local clone:

*** /home/belg4mit/nmh/test/testdir/7912.expected       Thu Apr 17 14:44:30 2014
--- /home/belg4mit/nmh/test/testdir/7912.actual Thu Apr 17 14:44:31 2014
***************
*** 1 ****
! /home/belg4mit/nmh/test/testdir/foo's bar
--- 1 ----
! ~/nmh/test/testdir/foo's bar ~/nmh 

./test/whatnow/test-cd: test failed, outputs are in 
/home/belg4mit/nmh/test/testdir/7912.expected and 
/home/belg4mit/nmh/test/testdir/7912.actual.
FAIL: test/whatnow/test-cd

It seems to be using the user's shell somehow, and I have cd aliased to pushd.

backup-prefix.patch
Description: backup-prefix.patch