Make ScheduleConfigTest pass in non-US locales

Gerrit's documentation states that it wants Mondays abbreviated as
'Mon' for gc.startTime, but the parsing code tried to parse the
abbreviated week day in default locale. As non-US locales need not
parse 'Mon' to a Monday (E.g.: German uses 'Mo' as abbreviation for
Monday and chokes on 'Mon'), we parse using the US locale.

Thereby, we make the code do what the docs require, and we make the
ScheduleConfigTest pass, if the default locale has different
abbreviations for Mondays.

Change-Id: I06e5b0e4299424dbcb5f0f9628b374b619e3c16f

gerrit-server/src/main/java/com/google/gerrit/server/config/ScheduleConfig.java

@@ -28,6 +28,7 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.text.MessageFormat;
+import java.util.Locale;
 import java.util.concurrent.TimeUnit;
 
 public class ScheduleConfig {
@@ -122,7 +123,8 @@ public class ScheduleConfig {
           startTime.hourOfDay().set(firstStartTime.getHourOfDay());
           startTime.minuteOfHour().set(firstStartTime.getMinuteOfHour());
         } catch (IllegalArgumentException e1) {
-          formatter = DateTimeFormat.forPattern("E HH:mm");
+          formatter = DateTimeFormat.forPattern("E HH:mm")
+              .withLocale(Locale.US);
           LocalDateTime firstStartDateTime = formatter.parseLocalDateTime(start);
           startTime.dayOfWeek().set(firstStartDateTime.getDayOfWeek());
           startTime.hourOfDay().set(firstStartDateTime.getHourOfDay());