Fix incorrect switching on tag for salt model generation job

When no one branch specified for cc-templates,reclass-system, mcp-common-scripts
should be used 'release/$mcp_version' instead of tag 'mcp_version'

Related-Prod: PROD-28865

Change-Id: I53d7ff688d2c04f3b4187392c89195b9eb4b66bb
diff --git a/generate-cookiecutter-products.groovy b/generate-cookiecutter-products.groovy
index d4be6cc..9ec7413 100644
--- a/generate-cookiecutter-products.groovy
+++ b/generate-cookiecutter-products.groovy
@@ -83,14 +83,14 @@
     }
     // Use mcpVersion git tag if not specified branch for cookiecutter-templates
     if (!context.get('cookiecutter_template_branch')) {
-        context['cookiecutter_template_branch'] = gitGuessedVersion ?: context['mcp_version']
+        context['cookiecutter_template_branch'] = gitGuessedVersion ?: "release/${context['mcp_version']}".toString()
     }
     // Don't have n/t/s for cookiecutter-templates repo, therefore use master
     if (["nightly", "testing", "stable"].contains(context['cookiecutter_template_branch'])) {
         context['cookiecutter_template_branch'] = 'master'
     }
     if (!context.get('shared_reclass_branch')) {
-        context['shared_reclass_branch'] = gitGuessedVersion ?: context['mcp_version']
+        context['shared_reclass_branch'] = gitGuessedVersion ?: "release/${context['mcp_version']}".toString()
     }
     // Don't have nightly/testing for reclass-system repo, therefore use master
     if (["nightly", "testing", "stable"].contains(context['shared_reclass_branch'])) {
@@ -98,7 +98,7 @@
     }
     if (!context.get('mcp_common_scripts_branch')) {
         // Pin exactly to CC branch, since it might use 'release/XXX' format
-        context['mcp_common_scripts_branch'] = gitGuessedVersion ?: context['mcp_version']
+        context['mcp_common_scripts_branch'] = gitGuessedVersion ?: "release/${context['mcp_version']}".toString()
     }
     // Don't have n/t/s for mcp-common-scripts repo, therefore use master
     if (["nightly", "testing", "stable"].contains(context['mcp_common_scripts_branch'])) {