Fix #143 READMEs suggest wrong cert name

Author: pitbulk

demo-bottle/saml/certs/README

@@ -3,9 +3,9 @@ Take care of this folder that could contain private key. Be sure that this folde
 Onelogin Python Toolkit expects that certs for the SP could be stored in this folder as:
 
  * sp.key   Private Key
- * sp.cert  Public cert
+ * sp.crt  Public cert
 
 Also you can use other cert to sign the metadata of the SP using the:
 
  * metadata.key
- * metadata.cert
+ * metadata.crt

demo-django/saml/certs/README

@@ -3,9 +3,9 @@ Take care of this folder that could contain private key. Be sure that this folde
 Onelogin Python Toolkit expects that certs for the SP could be stored in this folder as:
 
  * sp.key   Private Key
- * sp.cert  Public cert
+ * sp.crt  Public cert
 
 Also you can use other cert to sign the metadata of the SP using the:
 
  * metadata.key
- * metadata.cert
+ * metadata.crt

demo-flask/saml/certs/README

@@ -3,9 +3,9 @@ Take care of this folder that could contain private key. Be sure that this folde
 Onelogin Python Toolkit expects that certs for the SP could be stored in this folder as:
 
  * sp.key   Private Key
- * sp.cert  Public cert
+ * sp.crt  Public cert
 
 Also you can use other cert to sign the metadata of the SP using the:
 
  * metadata.key
- * metadata.cert
+ * metadata.crt