t0050-filesystem.sh unicode tests borked on dash shell

I noticed recently that the unicode tests, when run by the dash shell,
have not been working as designed. (The tests *pass*, but they are
*not* testing what was intended)

In order to demonstrate, I added an "false &&" line after the touch in
test #8, so that (on Ubuntu):

    $ ./t0050-filesystem -i
    ok 1 - see what we expect
    ok 2 - detection of case insensitive filesystem during repo init
    ok 3 - detection of filesystem w/o symlink support during repo init
    ok 4 - setup case tests
    ok 5 - rename (case change)
    ok 6 - merge (case change)
    not ok 7 - add (with different case) # TODO known breakage
    not ok - 8 setup unicode normalization tests
    #	
    #	
    #	  test_create_repo unicode &&
    #	  cd unicode &&
    #	  touch "$aumlcdiar" &&
    #	false &&
    #	  git add "$aumlcdiar" &&
    #	  git commit -m initial &&
    #	  git tag initial &&
    #	  git checkout -b topic &&
    #	  git mv $aumlcdiar tmp &&
    #	  git mv tmp "$auml" &&
    #	  git commit -m rename &&
    #	  git checkout -f master
    #	
    #	
    $ ls trash\ directory.t0050-filesystem/unicode/
    \x61\xcc\x88

    $ bash t0050-filesystem -i
    ok 1 - see what we expect
    ok 2 - detection of case insensitive filesystem during repo init
    ok 3 - detection of filesystem w/o symlink support during repo init
    ok 4 - setup case tests
    ok 5 - rename (case change)
    ok 6 - merge (case change)
    not ok 7 - add (with different case) # TODO known breakage
    not ok - 8 setup unicode normalization tests
    #	
    #	
    #	  test_create_repo unicode &&
    #	  cd unicode &&
    #	  touch "$aumlcdiar" &&
    #	false &&
    #	  git add "$aumlcdiar" &&
    #	  git commit -m initial &&
    #	  git tag initial &&
    #	  git checkout -b topic &&
    #	  git mv $aumlcdiar tmp &&
    #	  git mv tmp "$auml" &&
    #	  git commit -m rename &&
    #	  git checkout -f master
    #	
    #	
    $ ls trash\ directory.t0050-filesystem/unicode/ | od -x
    0000000 cc61 0a88
    0000004

So bash works fine and I can avoid the problem by running the tests, thus:

    $ SHELL_PATH=/bin/bash make NO_SVN_TESTS=1 test

Since I have an older dash, I compiled dash from source (my dash git repo
claims:

    $ git describe --tags
    v0.5.6-24-gb61ab0b

), but the result was exactly the same.

I afraid I don't have time to investigate this further at the moment ...

ATB,
Ramsay Jones