upas/fs: use mime names directly with tcs
 [rsc] --rw-rw-r-- M 177229 glenda sys 4189 Apr  1 17:18 sys/src/cmd/upas/fs/dat.h
	/n/sourcesdump/2006/0401/plan9/sys/src/cmd/upas/fs/dat.h:132,139 - 
	/n/sourcesdump/2006/0402/plan9/sys/src/cmd/upas/fs/dat.h:132,137
	  void		decode(Message*);
	  int		cistrncmp(char*, char*, int);
	  int		cistrcmp(char*, char*);
	- int		latin1toutf(char*, char*, char*);
	- int		windows1257toutf(char*, char*, char*);
	  int		decquoted(char*, char*, char*, int);
	  int		xtoutf(char*, char**, char*, char*);
	  void		countlines(Message*);
 [rsc] --rw-rw-r-- M 177229 glenda sys 26924 Apr  1 22:01 sys/src/cmd/upas/fs/fs.c
	[diffs elided - too long]
	[diff -c /n/sourcesdump/2006/0401/plan9/sys/src/cmd/upas/fs/fs.c /n/sourcesdump/2006/0402/plan9/sys/src/cmd/upas/fs/fs.c]
 [rsc] --rw-rw-r-- M 177229 glenda sys 26636 Apr  1 17:18 sys/src/cmd/upas/fs/mbox.c
	[diffs elided - too long]
	[diff -c /n/sourcesdump/2006/0401/plan9/sys/src/cmd/upas/fs/mbox.c /n/sourcesdump/2006/0402/plan9/sys/src/cmd/upas/fs/mbox.c]
 [rsc] --rw-rw-r-- M 177229 glenda sys 26924 Apr  1 22:01 sys/src/cmd/upas/fs/fs.c
 [rsc] --rw-rw-r-- M 177229 rsc sys 1146 Apr  1 22:03 sys/src/cmd/upas/fs/rfc2047-test