Description of problem:

When attempting to graph from say 7am to 12pm in a non-Latin locale, Spacewalk will display an error claiming that the end time is before the start time.

Steps to Reproduce:
1. Enable monitoring on your spacewalk installation.
2. Add monitoring entitlement to a registered system.
3. Open the Monitoring tab in the SDC and create a probe for this system, preferably something that can be graphed such as load average.
4. Change your account locale preferences to German and timezone to something European, GMT+0100 should work.
5. Navigate back to the monitoring page, view the probe details, and select to graph from 07:00 to 12:00. (make sure to set the date to the same day)
  
Actual results:

Error message which, if translated, roughly states that the end date is before the start date.

Expected results:

This should work.

Additional info:

Problem is related to an ill-thought out hack in DatePicker.java where incoming hour of 12 is immediately changed to 0, and 0 is changed back to 12 outgoing, with no attention paid to whether or not the locale is even latin and if so, what the value of AM/PM is.