[birt-dev]CheckIn: Fix Bugzilla Bug 162827 --- Blank bookmark can belink

["Wei Zhao (Shang)" <wei.zhao@xxxxxxxxxxx>]

Title: [birt-dev]CheckIn: Fix Bugzilla Bug 162827 --- Blank bookmark can belinked to in pdf but cannot in html and viewer.

- Summary:
Rollback the TOC change.

- Bugzilla Bug (s) Resolved:
Fix Bugzilla Bug 162827 --- Blank bookmark can belinked to in pdf but cannot in html and viewer

- Description:
For TOC it is different as the TOC is a display string instead of an ID. The ID can't be null or empty string while the display string can be empty string.

So we only need to fix bookmark.

- Tests Description  :
Manual Test.

- Notes to Build Team:

- Notes to Developers:

- Notes to QA:  
 
- Notes to Documentation:  

- Files Edited:
"/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/executor/ReportItemExecutor.java"

- Files Added:

- Files Deleted

-Wei Zhao( Shanghai )