add mysql container to the build environment jenkins slave pod

Former-commit-id: 50e27081b8d79ccd1c0ffc01a3de16e142feb7ac

ci/jenkins/pod/milvus-build-env-pod.yaml

@@ -20,18 +20,6 @@ spec:
       requests:
         memory: "16Gi"
         cpu: "4.0"
-
----
-
-apiVersion: v1
-kind: Pod
-metadata:
-  name: milvus-mysql
-  labels:
-    app: milvus
-    componet: mysql
-spec:
-  containers:
   - name: milvus-mysql
     image: mysql:5.6
     env: