factotum: add httpdigest client protocol
 [rsc] --rw-rw-r-- M 1635703 glenda sys 4991 Feb 23 06:41 sys/src/cmd/auth/factotum/dat.h
	/n/sourcesdump/2006/0223/plan9/sys/src/cmd/auth/factotum/dat.h:234,236 - 
	/n/sourcesdump/2006/0224/plan9/sys/src/cmd/auth/factotum/dat.h:234,237
	  extern Proto rsa;			/* rsa.c */
	  extern Proto wep;			/* wep.c */
	  /* extern Proto srs;			/* srs.c */
	+ extern Proto httpdigest;		/* httpdigest.c */
 [rsc] --rw-rw-r-- M 1635703 glenda sys 10558 Feb 23 06:41 sys/src/cmd/auth/factotum/fs.c
	/n/sourcesdump/2006/0223/plan9/sys/src/cmd/auth/factotum/fs.c:29,34 - 
	/n/sourcesdump/2006/0224/plan9/sys/src/cmd/auth/factotum/fs.c:29,35
	  	&apop,
	  	&chap,
	  	&cram,
	+ 	&httpdigest,
	  	&mschap,
	  	&p9any,
	  	&p9cr,
 [rsc] --rw-rw-r-- M 1635703 rsc sys 3481 Feb 23 06:41 sys/src/cmd/auth/factotum/httpdigest.c
 [rsc] --rw-rw-r-- M 1635703 glenda sys 497 Feb 23 06:41 sys/src/cmd/auth/factotum/mkfile
	/n/sourcesdump/2006/0223/plan9/sys/src/cmd/auth/factotum/mkfile:6,11 - 
	/n/sourcesdump/2006/0224/plan9/sys/src/cmd/auth/factotum/mkfile:6,12
	  PROTO=\
	  	apop.$O\
	  	chap.$O\
	+ 	httpdigest.$O\
	  	p9any.$O\
	  	p9cr.$O\
	  	p9sk1.$O\