Fix swagger errors (#4220)

Fix all the resting errors to have a valid swagger file.

They are still some warnings but nothing blocking.

Doing so I found that some request still misses son parameters for some POST/PUT/PATCH request. This means the a client generated from the swagger file will not work completely. 

Fix #4088 by activating validation in drone
Should fix #4010.

routers/api/v1/repo/issue_comment.go

@@ -31,7 +31,7 @@ func ListIssueComments(ctx *context.APIContext) {
 	//   description: name of the repo
 	//   type: string
 	//   required: true
-	// - name: id
+	// - name: index
 	//   in: path
 	//   description: index of the issue
 	//   type: integer
@@ -139,7 +139,7 @@ func CreateIssueComment(ctx *context.APIContext, form api.CreateIssueCommentOpti
 	//   description: name of the repo
 	//   type: string
 	//   required: true
-	// - name: id
+	// - name: index
 	//   in: path
 	//   description: index of the issue
 	//   type: integer