Description of problem:
when a process instance has more than 10 variables, the page number is changed all the time.

Version-Release number of selected component (if applicable):
6.1.0

How reproducible:
100%

Steps to Reproduce:
1. Go to bpms site process instances page.
2. Find a process instance which has more than 10 variables and click the process instance, go to process variables page.
3. Click the next page button.

Actual results:
The next page button can be clicked without limitation, and the page number is increased all the time.

Expected results:
The next page button can not be clicked until it reached the maximum page number.

Additional info: