hangover of unix days in tmac.s - references /usr/bin/col which has moved in plan9.

Reference: /n/sources/patch/applied/unix-in-tmac
Date: Fri Feb 15 10:47:23 CET 2013
Signed-off-by: steve@quintile.net

--- /sys/lib/tmac/tmac.s	Fri Feb 15 10:46:53 2013
+++ /sys/lib/tmac/tmac.s	Fri Feb 15 10:46:47 2013
@@ -106,7 +106,7 @@
 .if !\\n(IM .if !\\n(MN .pn 0
 .so \\*(sd/tmac.scover
 .if !\\n(IM .if !\\n(MN .rm IM MF MR
-.if n .if !\\n(.T .pi /usr/bin/col
+.if n .if !\\n(.T .pi /bin/col
 .nr ST 1
 .ds QF TECHNICAL MEMORANDUM
 .br