[birt-dev]CheckIn: Fix Bugzilla Bug 156838 --- Method name spelling erro

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

Title: [birt-dev]CheckIn: Fix Bugzilla Bug 156838 --- Method name spelling error in IScriptStyle

- Summary:
Change BackgroundAttachement to BackgroundAttachment.

- Bugzilla Bug (s) Resolved:
Fix Bugzilla Bug 156838 --- Method name spelling error in IScriptStyle

- Description:
Write the wrong word.

- Tests Description  :
Unit 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/api/script/instance/IScriptStyle.java"
"/org.eclipse.birt.report.engine/test/org/eclipse/birt/report/engine/api/script/instance/InstanceTest.java"
"/org.eclipse.birt.report.engine/src/org/eclipse/birt/report/engine/script/internal/instance/StyleInstance.java"

- Files Added:

- Files Deleted

-Wei Zhao(Shanghai)