Cannot set date of Samigo while set JAVA_OPTS's locale to zh_CN

This is reported by Fudan University:

When set JVM_OPTION's locale to zh_CN, users can not set the date of a quiz(include start time, end time...). An error was post in log:org.sakaiproject.tool.assessment.ui.listener.util.TimeUtil - can not parse the string into a Date

Because in simplified Chinese, the valid date string is something like 10/28/2010 12:52:01 XX (PM in Chinese characters), yet the date picker page put 10/28/2010 12:52:01 AM in the page field. This generate a DateFormatException.
Since the date picker page has not supported i18n, here's our solution.
Use new SimpleDateFormat(displayDateFormat, Locale.US) instead of new SimpleDateFormat(displayDateFormat) in files below:
samigo-app/src/java/org/sakaiproject/tool/assessment/ui/bean/author/AssessmentSettingsBean.java, line 1493, version 2.7.0
samigo-app/src/java/org/sakaiproject/tool/assessment/ui/bean/author/PublishedAssessmentSettingsBean.java, line 1317, version 2.7.0

We hope the date picker page could support i18n in future.