Summary
	* Issue title:  Impossibility to delete a node without Version History
	* Product Jira Issue: JCR-2086.
	* Complexity: N/A

Proposal
 
Problem description

What is the problem to fix?
	* While trying to delete the content of a site, we can get several type of exception such as NPE or "Version history is not found. UUID: 9696dba0c0a803020165c955703dbf31. Context item (ancestor to save)"

Fix description

Problem analysis
	* The user upload the site content without the history so when he tries to delete it the JCR detects that we try to remove a node mix:versionable that doesn't have any history in the system workspace

How is the problem fixed?
	* We made the code more flexible to prevent NPE on places where NPE could be raised and we now only log a message at debug level instead of throwing an exception when the JCR detects a missing history 

Tests to perform

Reproduction test
	* Import a node which was exported without version history
        * Verify that we can delete this node via Crash, Webdav 

Tests performed at DevLevel
        * The test case TestImportVersionedChild has been modified to make sure that the JCR doesn't throw any RepositoryException in case of a missing history	
Tests performed at Support Level
	* Upload the site and make sure that we can remove it using CraSH or webdav

Tests performed at QA
	*

Changes in Test Referential

Changes in SNIFF/FUNC/REG tests
	* 

Changes in Selenium scripts 
	* 

Documentation changes

Documentation (User/Admin/Dev/Ref) changes:
	* No

Configuration changes

Configuration changes:
	* No

Will previous configuration continue to work?
	* Yes

Risks and impacts

Can this bug fix have any side effects on current client projects?
	* Any change in API (name, signature, annotation of a class/method)? 
	* Data (template, node type) migration/upgrade:  No

Is there a performance risk/cost?
	* No
