Whitelist some Launch Daemons

Fixes for two issues I ran into on an iMac running 10.9.5 (updated from 10.9.3)

1: I have the following Launch Daemons running:
```
locate.updatedb
 path: /usr/libexec/locate.updatedb
 plist: /System/Library/LaunchDaemons/com.apple.locate.plist
 hash: e8cc729ae05233c414eb0c672d836fc1

configureLocalKDC
 path: /usr/libexec/configureLocalKDC
 plist: /System/Library/LaunchDaemons/com.apple.configureLocalKDC.plist
 hash: 19f6e328d0286ad7f81ee8224e369726

ntpd-wrapper
 path: /usr/libexec/ntpd-wrapper
 plist: /System/Library/LaunchDaemons/org.ntp.ntpd.plist
 hash: baf0968c6df24734e079baeb01851221
```

This patch whitelists them.

Here's the source of each Launch Daemon configuration file and the man page for each command from Apple:
locate.updatedb : [plist](http://www.opensource.apple.com/source/shell_cmds/shell_cmds-175/locate/locate/com.apple.locate.plist) [manpage](https://developer.apple.com/library/mac/documentation/Darwin/Reference/Manpages/man8/locate.updatedb.8.html)
configureLocalKDC : [plist](http://www.opensource.apple.com/source/KerberosHelper/KerberosHelper-114.3/com.apple.configureLocalKDC.plist) [manpage](https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man1/configureLocalKDC.1.html)
ntpd-wrapper : [plist](http://www.opensource.apple.com/source/ntp/ntp-88/org.ntp.ntpd.plist) [manpage](https://developer.apple.com/library/mac/documentation/Darwin/Reference/Manpages/man8/ntpd-wrapper.8.html)
FYI the md5s are good for 10.10 too - These files don't appear to change often.

2: Make knockknock.py executable by double-clicking on it in Finder or running `./knockknock.py` in Terminal because why not?