term: fix build on solaris

These build tags were copied by mistake to term_solaris.go. Remove them
to fix the build on solaris.

Change-Id: I0d6c4a1bd3a9dcbb9973051cff93819ba28f1fa8
Reviewed-on: https://go-review.googlesource.com/c/term/+/201418
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/term_solaris.go b/term_solaris.go
index cd6feae..4bdb61a 100644
--- a/term_solaris.go
+++ b/term_solaris.go
@@ -2,8 +2,6 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
-// +build aix darwin dragonfly freebsd linux netbsd openbsd
 package term
 import (