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>

src/plugins/clearcase/clearcaseplugin.h

@@ -89,7 +89,8 @@ public:
         CheckedOut = 0x02,
         Hijacked   = 0x04,
         NotManaged = 0x08,
-        Missing    = 0x10
+        Missing    = 0x10,
+        Derived    = 0x20
     } status;
 
     QFile::Permissions permissions;