Remove extra text from nginx/frontend.crt as it breaks nginx

This line of text after the key in frontend.crt prevents me from starting up nginx on my mac with the following error:

```
nginx: [emerg] SSL_CTX_use_certificate_chain_file("/usr/local/etc/nginx/frontend.crt") failed (SSL: error:0D0680A8:asn1 encoding routines:ASN1_CHECK_TLEN:wrong tag error:0D07803A:asn1 encoding routines:ASN1_ITEM_EX_D2I:nested asn1 error error:0906700D:PEM routines:PEM_ASN1_read_bio:ASN1 lib error:140DC009:SSL routines:SSL_CTX_use_certificate_chain_file:PEM lib)
```

Presumably other people will get the same error, therefore I propose removing the text.