uucp bugs

[utzoo!henry]

In the distributed V7 uucp, uucp/chkpth.c/rdpth() has three separate bugs:

1. Chaos and madness will ensue if there are more than 15 entries in the
	USERFILE, because the Upt table has been misdeclared so that its
	overflow check is against the wrong number.  Fix:  change the
	"15" in the declaration of Upt (about line 16) to "MAXUSERS".

2. Chaos and madness may ensue if there is no comma in the first field of
	a USERFILE line.  Fix:  change the line (about line 130)
		pc = u + strlen(u->us_lname);
	to
		pc = us->us_lname + strlen(u->us_lname);

3. Any transfer request from a site with an 8-character (or longer)
	system name will fail, giving PERMISSION (DENIED).  Unlike
	all other uucp routines, rdpth is not truncating the system names
	it reads from USERFILE to 7 characters max length.  Fix:  after
	the line (about line 131):
		u->us_mname = pc;
	add:
		if (strlen(u->us_mname) > 7)
			u->us_mname[7] = '\0';