build, cmd, lib: Minimum supported compiler version is Go 1.5

lib/model/queue_test.go

@@ -273,7 +273,7 @@ func BenchmarkJobQueuePushPopDone10k(b *testing.B) {
 		for _, f := range files {
 			q.Push(f.Name, 0, time.Time{})
 		}
-		for _ = range files {
+		for range files {
 			n, _ := q.Pop()
 			q.Done(n)
 		}

lib/protocol/vector_test.go

@@ -144,7 +144,7 @@ func TestCompare(t *testing.T) {
 		// Empty vectors are identical
 		{Vector{}, Vector{}, Equal},
 		{Vector{}, Vector{[]Counter{{42, 0}}}, Equal},
-		{Vector{[]Counter{Counter{42, 0}}}, Vector{}, Equal},
+		{Vector{[]Counter{{42, 0}}}, Vector{}, Equal},
 
 		// Zero is the implied value for a missing Counter
 		{

lib/versioner/staggered.go

@@ -77,7 +77,7 @@ func NewStaggered(folderID, folderPath string, params map[string]string) Version
 		if testCleanDone != nil {
 			close(testCleanDone)
 		}
-		for _ = range time.Tick(time.Duration(cleanInterval) * time.Second) {
+		for range time.Tick(time.Duration(cleanInterval) * time.Second) {
 			s.clean()
 		}
 	}()