linter fixes (#5733)

* make .golangcy.yml work with Goland's Golint plugin

Explicitly disable all linters. Whitelist of enabled
plugins is already provided.

This would enable Goland users to user Golint plugin.

* fix deadcode warnings

* fix gocritic error

unslice: could simplify pkBytes[:] to pkBytes

.golangci.yml

@@ -3,6 +3,7 @@
 #   timeout: 5m
 
 linters:
+  disable-all: true
   enable:
     - bodyclose
     - deadcode
@@ -30,8 +31,6 @@ linters:
     - unconvert
     - unused
     - misspell
-  disable:
-    - errcheck
 
 issues:
   exclude-rules:

x/gov/keeper/test_common.go

@@ -56,10 +56,6 @@ var (
 	pubkeys = []crypto.PubKey{
 		delPk1, delPk2, delPk3, valOpPk1, valOpPk2, valOpPk3,
 	}
-
-	emptyDelAddr sdk.AccAddress
-	emptyValAddr sdk.ValAddress
-	emptyPubkey  crypto.PubKey
 )
 
 // TODO: remove dependency with staking
@@ -76,7 +72,7 @@ func newPubKey(pk string) (res crypto.PubKey) {
 		panic(err)
 	}
 	var pkEd ed25519.PubKeyEd25519
-	copy(pkEd[:], pkBytes[:])
+	copy(pkEd[:], pkBytes)
 	return pkEd
 }