Fix linter issues: misspell

Makefile

@@ -109,7 +109,7 @@ docker-test:
 	docker run --rm -v $(PWD):/go/src/$(CLONE_URL) -w /go/src/$(CLONE_URL) golang:$(GO_VERSION) go test -tags='$(BUILD_TAGS)' $(TESTFLAGS) ./...
 
 metalinter:
-	gometalinter --vendor --disable-all --enable=gotype --enable=gotypex --enable=gofmt --enable=goimports --deadline=60s --exclude "^internal/.*\.pb\.go" ./...
+	gometalinter --vendor --disable-all --enable=gotype --enable=gotypex --enable=gofmt --enable=goimports --enable=misspell --deadline=60s --exclude "^internal/.*\.pb\.go" ./...
 
 ######################
 # Build dependencies #

attr.go

@@ -46,7 +46,7 @@ type AttrStore interface {
 var nopStore AttrStore = nopAttrStore{}
 
 // newNopAttrStore returns an attr store which does nothing. It returns a global
-// object to avoid unecessary allocations.
+// object to avoid unnecessary allocations.
 func newNopAttrStore(string) AttrStore { return nopStore }
 
 // nopAttrStore represents a no-op implementation of the AttrStore interface.

client.go

@@ -5,7 +5,7 @@ import (
 	"io"
 )
 
-// Bit represents the intersection of a row and a column. It can be specifed by
+// Bit represents the intersection of a row and a column. It can be specified by
 // integer ids or string keys.
 type Bit struct {
 	RowID     uint64

enterprise/b/btree.go

@@ -494,7 +494,7 @@ func (t *tree) overflow(p *x, q *d, pi, i int, k uint64, v *roaring.Container) {
 	// data items up to the index of the new data item.
 	if l != nil && l.c < 2*kd && i != 0 {
 		s := (2*kd-l.c)/2 + 1 // half plus one
-		//s := 2*kd - l.c // all avaiable
+		//s := 2*kd - l.c // all available
 		if i < s {
 			s = i
 		}

lru/lru.go

@@ -25,7 +25,7 @@ type Cache struct {
 	// an item is evicted. Zero means no limit.
 	maxEntries int
 
-	// OnEvicted optionally specificies a callback function to be
+	// OnEvicted optionally specifies a callback function to be
 	// executed when an entry is purged from the cache.
 	OnEvicted func(key Key, value interface{})