ClearCase: Improved performance for indexing dynamic views

For dynamic views we only at initial sync/indexing check for checked out
files. When a file is opened it will be reindexed if needed. The very time
consuming recursive listing of all vobs is not needed as for snapshot
views.

Change-Id: I83d4ab70efdd311b6f3239ab45569c6d1810e10f
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
ClearCase: Handle Derived Objects

Derived Objects (DO) should not be checked in or out. Ideally they should
not be edited at all, but in the case where a user by accident opens
a DO and it is read only do not offer to vcsOpen() the file.

Change-Id: I5aee9655ca8696c6d7291950946052261526c751
Reviewed-by: Orgad Shaneh <orgads@gmail.com>
ClearCase: Give warning if editing a Derived Object

Derived objects (DO) are created during builds with ClearCase build
tools (e.g., clearmake). They are used for build avoidance and derived
object sharing. DOs are typically object files, but can also be source
code generated from code generation tools. It is probably never a good
idea to edit such a file.

Change-Id: If4248f09409424ee771aab720851bb6ce1aa40c9
Reviewed-by: Orgad Shaneh <orgads@gmail.com>