Fix display of package status for undelivered UPS packages.

Before this patch it would assume with any activity that it was delivered and would therefore show misleading information unless the package was delivered. Now it does not have a delivered on date if it isn't delivered and it shows the proper status. E.g.: In-Transit (On-Time)
http://screencast.com/t/ppYVLKnYsf
Merge branch 'hotfix/ISSUE-151'
Merge branch 'patch-1' of github.com:colinmollenhour/mageplus into hotfix/ISSUE-149
Merge branch 'hotfix/ISSUE-149' into develop