Fix backend linter errors

pkg/httpclient/httpclient.go

@@ -6,6 +6,7 @@ import (
 	"time"
 
 	simplejson "github.com/bitly/go-simplejson"
+
 	"github.com/grafana/grafana-plugin-sdk-go/backend"
 	"github.com/grafana/grafana-plugin-sdk-go/backend/httpclient"
 	"github.com/grafana/grafana-plugin-sdk-go/backend/log"
@@ -14,6 +15,10 @@ import (
 // New creates new HTTP client.
 func New(dsInfo *backend.DataSourceInstanceSettings, timeout time.Duration) (*http.Client, error) {
 	clientOptions, err := dsInfo.HTTPClientOptions()
+	if err != nil {
+		return nil, err
+	}
+
 	clientOptions.Timeouts.Timeout = timeout
 
 	tlsSkipVerify, err := getTLSSkipVerify(dsInfo)