ClearCase: Blame and linecount are wrong when parent of a filerevision is excluded because of branch exclusions.

When a branch is excluded, FE won't be able to set up the ancestor links correctly between a file revision on an included branch that is branched from an excluded branch. As a result, the linecount for the \0 version on the included branch will be 0 and the blame for the lines in the original file will be missing.

The fix is to treat the \0 as an addition and get the file contents from cleartool to determine the correct number of lines.