Refactoring ineffectual assignments

This patch fixed below 4 types of code line
1. Remove unnecessary variable assignment
2. Use variables declaration instead of explicit initial zero value
3. Change variable name to underbar when variable not used
4. Add erro check and return for ignored error

Signed-off-by: Daehyeok Mun <daehyeok@gmail.com>

command/container/stats_helpers.go

@@ -81,14 +81,11 @@ func collect(ctx context.Context, s *formatter.ContainerStats, cli client.APICli
 	go func() {
 		for {
 			var (
-				v                 *types.StatsJSON
-				memPercent        = 0.0
-				cpuPercent        = 0.0
-				blkRead, blkWrite uint64 // Only used on Linux
-				mem               = 0.0
-				memLimit          = 0.0
-				memPerc           = 0.0
-				pidsStatsCurrent  uint64
+				v                      *types.StatsJSON
+				memPercent, cpuPercent float64
+				blkRead, blkWrite      uint64 // Only used on Linux
+				mem, memLimit, memPerc float64
+				pidsStatsCurrent       uint64
 			)
 
 			if err := dec.Decode(&v); err != nil {

command/plugin/create.go

@@ -41,7 +41,9 @@ func validateConfig(path string) error {
 // validateContextDir validates the given dir and returns abs path on success.
 func validateContextDir(contextDir string) (string, error) {
 	absContextDir, err := filepath.Abs(contextDir)
-
+	if err != nil {
+		return "", err
+	}
 	stat, err := os.Lstat(absContextDir)
 	if err != nil {
 		return "", err