Fix reverse proxy shows 404 not found when Istio enabled (#1377)

Istio sidecar proxy blocks all requests sent through the reverse proxy
to the target service if the request.Host is not properly set to the
internal target service host. This PR sets the target service hosts
before establishing the proxy for the client in order to pass the
Istio sidecar proxy check.

pkg/fission-cli/logdb/influxdb.go

@@ -27,6 +27,7 @@ import (
 	"time"
 
 	influxdbClient "github.com/influxdata/influxdb/client/v2"
+	"github.com/pkg/errors"
 
 	ferror "github.com/fission/fission/pkg/error"
 	"github.com/fission/fission/pkg/fission-cli/log"
@@ -143,7 +144,7 @@ func (influx InfluxDB) query(query influxdbClient.Query) (*influxdbClient.Respon
 	queryURL.Path = path.Clean(fmt.Sprintf("%s/proxy/%s", queryURL.Path, INFLUXDB))
 	req, err := http.NewRequest(http.MethodPost, queryURL.String(), nil)
 	if err != nil {
-		return nil, err
+		return nil, errors.Wrap(err, "error creating request for log proxy")
 	}
 
 	parametersBytes, err := json.Marshal(query.Parameters)