test-dispatch: stabilize the test

When cwd is removed and `hg` is executed, some shells may run `getcwd`
before forking and executing, some may not do it, some may print a
different error message.

The test should be shell-independent so let's just avoid checking the error
message.

Differential Revision: https://phab.mercurial-scm.org/D1282

tests/test-dispatch.t

@@ -1,76 +1,80 b''
 test command parsing and dispatch
 
   $ hg init a
   $ cd a
 
 Redundant options used to crash (issue436):
   $ hg -v log -v
   $ hg -v log -v x
 
   $ echo a > a
   $ hg ci -Ama
   adding a
 
 Missing arg:
 
   $ hg cat
   hg cat: invalid arguments
   hg cat [OPTION]... FILE...
   
   output the current or given revision of files
   
   options ([+] can be repeated):
   
    -o --output FORMAT       print output to file with formatted name
    -r --rev REV             print the given revision
       --decode              apply any matching decode filter
    -I --include PATTERN [+] include names matching the given patterns
    -X --exclude PATTERN [+] exclude names matching the given patterns
   
   (use 'hg cat -h' to show more help)
   [255]
 
 [defaults]
 
   $ hg cat a
   a
   $ cat >> $HGRCPATH <<EOF
   > [defaults]
   > cat = -r null
   > EOF
   $ hg cat a
   a: no such file in rev 000000000000
   [1]
 
   $ cd "$TESTTMP"
 
 OSError "No such file or directory" / "The system cannot find the path
 specified" should include filename even when it is empty
 
   $ hg -R a archive ''
   abort: *: '' (glob)
   [255]
 
 #if no-outer-repo
 
 No repo:
 
   $ hg cat
   abort: no repository found in '$TESTTMP' (.hg not found)!
   [255]
 
 #endif
 
 #if rmcwd
 
 Current directory removed:
 
   $ mkdir $TESTTMP/repo1
   $ cd $TESTTMP/repo1
   $ rm -rf $TESTTMP/repo1
-  $ HGDEMANDIMPORT=disable hg version -q
-  abort: error getting current working directory: * (glob) (no-chg !)
-  chg: abort: failed to getcwd (errno = *) (glob) (chg !)
-  [255]
+
+The output could be one of the following and something else:
+ chg: abort: failed to getcwd (errno = *) (glob)
+ abort: error getting current working directory: * (glob)
+ sh: 0: getcwd() failed: No such file or directory
+Since the exact behavior depends on the shell, only check it returns non-zero.
+  $ HGDEMANDIMPORT=disable hg version -q 2>/dev/null || false
+  [1]
 
 #endif