avoid useless delay after creating maildir box

we would see the recent timestamp of the creation and conclude that
something is going on, so we'd wait. this is obviously nonsense.
as we know that a freshly created mailbox is empty, simply skip the
message scan alltogether.

src/drv_maildir.c

@@ -66,7 +66,7 @@ typedef struct maildir_message {
 
 typedef struct maildir_store {
 	store_t gen;
-	int uvfd, uvok, nuid;
+	int uvfd, uvok, nuid, fresh;
 	int minuid, maxuid, newuid, nexcs, *excs;
 	char *trash;
 #ifdef USE_DB
@@ -355,6 +355,7 @@ maildir_validate( const char *box, int create, maildir_store_t *ctx )
 			sys_error( "Maildir error: cannot access mailbox '%s'", buf );
 			return DRV_BOX_BAD;
 		}
+		ctx->fresh = 1;
 	} else {
 		for (i = 0; i < 3; i++) {
 			memcpy( buf + bl, subdirs[i], 4 );
@@ -385,6 +386,7 @@ maildir_validate( const char *box, int create, maildir_store_t *ctx )
 			}
 		}
 		closedir( dirp );
+		ctx->fresh = 0;
 	}
 	return DRV_OK;
 }
@@ -1026,6 +1028,9 @@ maildir_load( store_t *gctx, int minuid, int maxuid, int newuid, int *excs, int
 	ctx->excs = nfrealloc( excs, nexcs * sizeof(int) );
 	ctx->nexcs = nexcs;
 
+	if (ctx->fresh)
+		goto dontscan;
+
 	if (maildir_scan( ctx, &msglist ) != DRV_OK) {
 		cb( DRV_BOX_BAD, aux );
 		return;
@@ -1035,6 +1040,7 @@ maildir_load( store_t *gctx, int minuid, int maxuid, int newuid, int *excs, int
 		maildir_app_msg( ctx, &msgapp, msglist.ents + i );
 	maildir_free_scan( &msglist );
 
+  dontscan:
 	cb( DRV_OK, aux );
 }