fix: change variable for enable proxy build

This MR is reflecting of our changes of the switch variable name in https://github.com/jprorama/CRI_XCBC/pull/497

.gitlab-ci.yml

@@ -114,7 +114,7 @@ build_http_proxy_image:
   tags:
     - build
   variables:
-    PROXY_ENABLE_VAR: "enable_ood_proxy"
+    PROXY_ENABLE_VAR: "enable_http_proxy"
   <<: *build_proxy_image_template
   rules:
     - if: $PIPELINE_TARGET == "build" && $BUILD_TARGET == "http-proxy"
@@ -127,7 +127,7 @@ build_ssh_proxy_image:
   tags:
     - build
   variables:
-    PROXY_ENABLE_VAR: "enable_sshpiper"
+    PROXY_ENABLE_VAR: "enable_ssh_proxy"
   <<: *build_proxy_image_template
   rules:
     - if: $PIPELINE_TARGET == "build" && $BUILD_TARGET == "ssh-proxy"