fix: correct linter errors

I missed some of the `let` definitions for the ca, cert, and key when
establishing the docker TLS connection.

DCO-1.1 Signed-off-by: Patrick Wagstrom <160672+pridkett@users.noreply.github.com>

server/docker.js

@@ -156,6 +156,10 @@ class DockerHost {
         let certPath = path.join(Database.dockerTLSDir, dirName, DockerHost.CertificateFileNameCert);
         let keyPath = path.join(Database.dockerTLSDir, dirName, DockerHost.CertificateFileNameKey);
 
+        let key;
+        let cert;
+        let ca;
+
         if (dockerType === "tcp") {
             if (fs.existsSync(keyPath) && fs.existsSync(certPath)) {
                 // Load the key and cert