don't panic (just print the error and move along)

fixes #233

mapblockaccessor/legacyblocks.go

@@ -54,7 +54,7 @@ func (a *MapBlockAccessor) FindNextLegacyBlocks(s settings.Settings, layers []*l
 				"z":   block.Pos.Z,
 				"err": err,
 			}
-			logrus.WithFields(fields).Error("mapblock-pars")
+			logrus.WithFields(fields).Error("mapblock-parse")
 
 			return nil, err
 		}

tilerendererjob/initial.go

@@ -21,7 +21,8 @@ func initialRender(ctx *app.App) {
 		result, err := ctx.MapBlockAccessor.FindNextLegacyBlocks(ctx.Settings, ctx.Config.Layers, ctx.Config.RenderingFetchLimit)
 
 		if err != nil {
-			panic(err)
+			logrus.Error("Error in initial rendering run, trying to continue: " + err.Error())
+			continue
 		}
 
 		if len(result.List) == 0 && !result.HasMore {