Update Deploy Docs host

The build conventions plugin does not support a property, so we must
override the configuration for docs.host to docs-ip.spring.io

Closes gh-1845

Jenkinsfile

@@ -113,7 +113,7 @@ try {
 					try {
 						withCredentials([file(credentialsId: 'docs.spring.io-jenkins_private_ssh_key', variable: 'DEPLOY_SSH_KEY')]) {
 							withEnv(["JAVA_HOME=${tool 'jdk8'}"]) {
-								sh './gradlew deployDocs --no-daemon --stacktrace -PdeployDocsSshKeyPath=$DEPLOY_SSH_KEY -PdeployDocsSshUsername=$SPRING_DOCS_USERNAME -PdeployDocsHost=docs-ip.spring.io'
+								sh './gradlew deployDocs --no-daemon --stacktrace -PdeployDocsSshKeyPath=$DEPLOY_SSH_KEY -PdeployDocsSshUsername=$SPRING_DOCS_USERNAME'
 							}
 						}
 					}

spring-session-docs/spring-session-docs.gradle

@@ -48,3 +48,9 @@ asciidoctor {
 			'version-release': releaseBuild,
 			'version-snapshot': snapshotBuild
 }
+
+remotes {
+    docs {
+        host = "docs-ip.spring.io"
+    }
+}