[common] Add Del method to gera.StringWrapMap

Author: teo

common/gera/stringmap.go

@@ -40,6 +40,7 @@ type StringMap interface {
 
 	Get(key string) (string, bool)
 	Set(key string, value string) bool
+	Del(key string) bool
 
 	Flattened() (map[string]string, error)
 	FlattenedParent() (map[string]string, error)
@@ -186,6 +187,16 @@ func (w *StringWrapMap) Set(key string, value string) (ok bool) {
 	return true
 }
 
+func (w *StringWrapMap) Del(key string) (ok bool) {
+	if w == nil || w.theMap == nil {
+		return false
+	}
+	if _, exists := w.theMap[key]; exists {
+		delete(w.theMap, key)
+	}
+	return true
+}
+
 func (w *StringWrapMap) Has(key string) bool {
 	_, ok := w.Get(key)
 	return ok