doc/go1.5.txt: log: LUTC flag

Change-Id: Ieadbd2b1ad442ba3eb2ad5f552d96c93ba3e5a2e
Reviewed-on: https://go-review.googlesource.com/8790Reviewed-by: Rob Pike <r@golang.org>

doc/go1.5.txt

@@ -30,6 +30,7 @@ encoding/base64: add unpadded encodings (https://golang.org/cl/1511)
 flag: new nicer format for PrintDefaults (https://go-review.googlesource.com/7330)
 go/ast: add Implicit field to ast.EmptyStmt; changed meaning of ast.EmptyStmt.Semicolon position (https://golang.org/cl/5720)
 log: add SetOutput functions (https://golang.org/cl/2686, https://golang.org/cl/3023)
+log: add LUTC flag (https://golang.org/cl/8761)
 math/big: add arbitrary precision Floats (many cl's)
 mime: add ExtensionByType (https://golang.org/cl/7444)
 mime/quotedprintable: new package (https://golang.org/cl/5940 + others)