Give a proper error message when the hg repo is not known
tree241b3d5002991c333e287e924ffc7c7e7d6dc921
-rw-r--r-- 42 .gitignore
-rw-r--r-- 341 Makefile
-rw-r--r-- 2594 README
-rwxr-xr-x 12764 hg-fast-export.py
-rwxr-xr-x 3125 hg-fast-export.sh
-rwxr-xr-x 4721 hg-reset.py
-rwxr-xr-x 1517 hg-reset.sh
-rwxr-xr-x 3277 hg2git.py
-rw-r--r-- 6336 svn-archive.c
-rw-r--r-- 5227 svn-fast-export.c
-rwxr-xr-x 5467 svn-fast-export.py