tests: use `pwd` instead of ${PWD} in test-convert-git.t - because of Solaris stable

tests: use `pwd` instead of ${PWD} in test-convert-git.t - because of Solaris

--- a/contrib/check-code.py	Wed Jan 30 10:57:28 2013 -0500
+++ b/contrib/check-code.py	Thu Jan 31 02:39:55 2013 +0100
@@ -78,7 +78,7 @@
   [
     (r'^function', "don't use 'function', use old style"),
     (r'^diff.*-\w*N', "don't use 'diff -N'"),
-    (r'\$PWD', "don't use $PWD, use `pwd`"),
+    (r'\$PWD|\${PWD}', "don't use $PWD, use `pwd`"),
     (r'^([^"\'\n]|("[^"\n]*")|(\'[^\'\n]*\'))*\^', "^ must be quoted"),
   ]
 ]

--- a/tests/test-convert-git.t	Wed Jan 30 10:57:28 2013 -0500
+++ b/tests/test-convert-git.t	Thu Jan 31 02:39:55 2013 +0100
@@ -307,7 +307,7 @@
   $ echo 'sub' >> foo
   $ git add foo
   $ commit -a -m 'addfoo'
-  $ BASE=${PWD}
+  $ BASE=`pwd`
   $ cd ..
   $ mkdir git-repo6
   $ cd git-repo6