Improvement to 14ce129cfcd: Use try/except and pass filename on errors
Without the second part, the error message would be
abort: Is a directory
instead of
abort: Is a directory: /home/user/.cvspass
adding b rev offset length base linkrev nodeid p1 p2 0 0 3 0 0 1e88685f5dde 000000000000 000000000000