[jenkins_common] defer to the default location for nginx_template_dir
[jenkins_common] defer to the default location for nginx_template_dir

This fixes a bug introduced in 6d5e7f30

gsehub/configuration,edx/configuration,mitodl/configuration,rue89-tech/configuration,hks-epod/configuration,arbrandes/edx-configuration,stvstnfrd/configuration,stvstnfrd/configuration,rue89-tech/configuration,edx/configuration,edx/configuration,appsembler/configuration,Stanford-Online/configuration,EDUlib/configuration,gsehub/configuration,gsehub/configuration,Stanford-Online/configuration,gsehub/configuration,stvstnfrd/configuration,hks-epod/configuration,stvstnfrd/configuration,mitodl/configuration,arbrandes/edx-configuration,arbrandes/edx-configuration,arbrandes/edx-configuration,EDUlib/configuration,arbrandes/edx-configuration,rue89-tech/configuration,rue89-tech/configuration,appsembler/configuration,rue89-tech/configuration,EDUlib/configuration,gsehub/configuration,mitodl/configuration,appsembler/configuration,EDUlib/configuration,hks-epod/configuration,Stanford-Online/configuration,stvstnfrd/configuration,edx/configuration,hks-epod/configuration,mitodl/configuration,hks-epod/configuration,EDUlib/configuration,appsembler/configuration,Stanford-Online/configuration,Stanford-Online/configuration