Move the ObjectAPI() resource to be beginning of each handlers.

We should return back proper errors so that the clients can
retry until server has been initialized.

cmd/api-errors.go

@@ -134,6 +134,7 @@ const (
 	ErrObjectExistsAsDirectory
 	ErrPolicyNesting
 	ErrInvalidObjectName
+	ErrServerNotInitialized
 	// Add new extended error codes here.
 	// Please open a https://github.com/minio/minio/issues before adding
 	// new error codes here.
@@ -556,6 +557,11 @@ var errorCodeResponse = map[APIErrorCode]APIError{
 		Description:    "Object name contains unsupported characters. Unsupported characters are `^*|\\\"",
 		HTTPStatusCode: http.StatusBadRequest,
 	},
+	ErrServerNotInitialized: {
+		Code:           "XMinioServerNotInitialized",
+		Description:    "Server not initialized, please try again.",
+		HTTPStatusCode: http.StatusServiceUnavailable,
+	},
 	// Add your error structure here.
 }