Look for password in both CVS and CVSNT password files.

Look for password in both CVS and CVSNT password files.

In conn, if password is not passed on command line, look for a password
entry in both the CVS password file and the CVSNT password file.  If only
one file is found and the requested repository is in that file, or if both
files are found but the requested repository is found in only one file, use
the password from the single file containing the repository entry.  If both
files are found and the requested repository is found in both files, then
produce an error message.

The CVS password file separates tokens with a space character, while
the CVSNT password file separates tokens with an equal (=) character.
Add a sub find_password_entry that accepts the password file name
and a delimiter to eliminate code duplication.

Signed-off-by: Guy Rouillier <guyr@burntmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>