tag: properly abort if an unknown or ignored .hgtags is present
This was a regression introduced by
4faaa0535ea7 in 2008.
summary: remove unused code for listing ignored files
The call to repo.status() does not request ignored files to be listed,
so remove the code for printing them.
fetch: use cmdutil.bailifchanged()
Use the existing method cmdutil.bailifchanged() instead of
implementing it again in fetch.py. An effect of this is that the error
messages in case of uncommited changes will be different.