Description of problem:
rhq metrics availability graph is not visible 

Version-Release number of selected component (if applicable):
build:

How reproducible:
always

Steps to Reproduce:
1. install rhq 4.9
2. rhq agent -> monitoring ->  Metrics
3. select non-default display interval
4. nativate to monitoring -> schedules
5. navigate back to monitoring -> metrics

Actual results:
no graph is visible

Expected results:
graph with default (8 hours) date should be visible

Additional info:

Expected -> http://d.pr/i/2ObZ
actual   -> http://d.pr/i/theQ