git-sh-setup: typofix in comments

Noticed by Anupam Srivastava.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

git-sh-setup.sh

@@ -6,7 +6,7 @@
 # it dies.
 
 # Having this variable in your environment would break scripts because
-# you would cause "cd" to be be taken to unexpected places.  If you
+# you would cause "cd" to be taken to unexpected places.  If you
 # like CDPATH, define it for your interactive shell sessions without
 # exporting it.
 unset CDPATH