Merge branch 'gn_bug_6902_ppt_back_img_1210@guomengyuan' into debug

controllers/ppt_v2.go

@@ -459,7 +459,7 @@ func (this *PptV2Controller) DetailPpt() {
 	}
 
 	// 维护封底 背景图
-	if pptInfo.CurrentBackgroundImg != "" {
+	if pptInfo.CurrentBackgroundImg == "" {
 		var condition string
 		var pars []interface{}
 
@@ -478,7 +478,7 @@ func (this *PptV2Controller) DetailPpt() {
 			pptInfo.CurrentBackgroundImgId = imageConfList[0].ImageConfId
 		}
 	}
-	if pptInfo.BackCoverImg != "" {
+	if pptInfo.BackCoverImg == "" {
 		var condition string
 		var pars []interface{}