Jenkinsfile: Reuse SSH credentials through SSH agent (hopefully).

Jenkinsfile

@@ -56,6 +56,7 @@ def perConfiguration(suffix, f) {
 // We need a Windows Server with Visual Studio 2015, Premake5 and Git on it.
 def doBuild(premakeFlags, configuration) {
 	node("windows") {
+		sshagent (credentials: ["ba9ec261-deff-4fa0-a0e8-5d755f88d035"]) {
 			checkout scm
 
 			premakeHome = "${pwd()}\\src\\tools"
@@ -71,6 +72,8 @@ def doBuild(premakeFlags, configuration) {
 			archiveArtifacts artifacts: "*", fingerprint: true
 			stash name: "iw4x $configuration", includes: "*"
 		}
+
+	}
 }
 
 // For each available configuration generate a normal build and a unit test build.