backport akuchling's checkin of

backport akuchling's checkin of
    revision 1.11 of install_scripts.py

Restrict the mode to the lowest four octal positions; higher positions
   contain the type of the file (regular file, socket, link, &c.).
   This means that install_scripts will now print
   "changing mode of <file> to 775" instead of "... to 100775".

2.2 bugfix candidate, I suppose, though this isn't actually fixing a bug.

This patch was applied by an alarmingly automated system -- I hope it
worked...