runtime: change odd 'print1_write' file names

The '1' part is left over from the C conversion, but no longer makes
sense given that print1.go no longer exists.

Change-Id: Iec171251370d740f234afdbd6fb1a4009fde6696
Reviewed-on: https://go-review.googlesource.com/16036
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

diff --git a/src/runtime/print1_write.go b/src/runtime/write_err.go
similarity index 100%
rename from src/runtime/print1_write.go
rename to src/runtime/write_err.go

diff --git a/src/runtime/print1_write_android.go b/src/runtime/write_err_android.go
similarity index 100%
rename from src/runtime/print1_write_android.go
rename to src/runtime/write_err_android.go