[birt-dev] Fix an error in the RAStreamBuffer implementation

["Houqiang Yan" <hyan@xxxxxxxxxxx>]

Title: Fix an error in the RAStreamBuffer implementation

- Summary:
Fix an error in last implementation. When a write is across multiple buffers, and the following buffers after first one are already in buffer pool, we didn't reset the next write position (bufCur) to 0. This checkin fixes this problem.

- Bugzilla Bug (s) Resolved:
None

- Description:
Fix an error in the RAStreamBuffer implementation

- Tests Description:
Manually Test with HQ benchmark report

- Notes to Build Team:

- Notes to Developers:

- Notes to QA:  
 
- Notes to Documentation:  

- Files Edited:
"/org.eclipse.birt.core/src/org/eclipse/birt/core/archive/RAStreamBufferMgr.java"

- Files Added:

- Files Deleted