Stop logging messages about using DOCKER_CONFIG

Since the GetDefaultAuthFile() is caused during podman init
it ends up logging the same info line multiple times, with
no way for the user to quiet the output.

Fixes https://github.com/containers/podman/issues/9473

Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>

common/pkg/auth/auth.go

@@ -22,9 +22,7 @@ import (
 func GetDefaultAuthFile() string {
 	authfile := os.Getenv("REGISTRY_AUTH_FILE")
 	if authfile == "" {
-		if authfile, ok := os.LookupEnv("DOCKER_CONFIG"); ok {
-			logrus.Infof("Using DOCKER_CONFIG environment variable for authfile path %s", authfile)
-		}
+		authfile = os.Getenv("DOCKER_CONFIG")
 	}
 	return authfile
 }