sha3: delete unused field

Change-Id: I7dcb8a5ee07cc39e0c503f211f8f77732f006ad6
Reviewed-on: https://go-review.googlesource.com/59170
Run-TryBot: Michael Munday <mike.munday@ibm.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
diff --git a/sha3/sha3.go b/sha3/sha3.go
index c86167c..b12a35c 100644
--- a/sha3/sha3.go
+++ b/sha3/sha3.go
@@ -42,9 +42,8 @@
 	storage [maxRate]byte
 
 	// Specific to SHA-3 and SHAKE.
-	fixedOutput bool            // whether this is a fixed-output-length instance
-	outputLen   int             // the default output size in bytes
-	state       spongeDirection // whether the sponge is absorbing or squeezing
+	outputLen int             // the default output size in bytes
+	state     spongeDirection // whether the sponge is absorbing or squeezing
 }
 
 // BlockSize returns the rate of sponge underlying this hash function.