Merge branch 'jc/maint-protect-sh-from-ifs' into maint-1.7.11

When the user exports a non-default IFS without HT, scripts that
rely on being able to parse "ls-files -s | while read a b c..."
start to fail.  Protect them from such a misconfiguration.

* jc/maint-protect-sh-from-ifs:
  sh-setup: protect from exported IFS

git-sh-setup.sh

@@ -9,8 +9,12 @@
 # you would cause "cd" to be taken to unexpected places.  If you
 # like CDPATH, define it for your interactive shell sessions without
 # exporting it.
+# But we protect ourselves from such a user mistake nevertheless.
 unset CDPATH
 
+# Similarly for IFS
+unset IFS
+
 git_broken_path_fix () {
 	case ":$PATH:" in
 	*:$1:*) : ok ;;