EmailChallenge: add requester's certificate name into the email content

Change-Id: I3231640daf0daa9edbac1fea694fbbbdcdb353fa
diff --git a/ndncert-mail.conf.sample b/ndncert-mail.conf.sample
index 492c1e5..a33e458 100644
--- a/ndncert-mail.conf.sample
+++ b/ndncert-mail.conf.sample
@@ -8,5 +8,5 @@
 [ndncert_email_settings]
 MAIL_FROM = NDN Testbed Certificate Robot <noreply-ndncert@named-data.net>
 SUBJECT = Email Challenge Triggered by NDNCERT
-TEXT_TEMPLATE = Your PIN code: {0} from NDNCERT CA {1}. Please keep it secret and type in to your application to finish the certificiate issuance process. If you do not know what is going on, please ignore the message.
-HTML_TEMPLATE = <html><head></head><body><p><b>Your PIN code: {0} from NDNCERT CA {1}</b></p><p>Please keep it secret and type in to your application to finish the certificiate issuance process. If you do not know what is going on, please ignore the message.</p><p>Sincerely,<br/>NDN Testbed NDNCERT robot</p>
\ No newline at end of file
+TEXT_TEMPLATE = Your PIN code: {0} from NDNCERT CA {1}. Certificate Name: {2}. Your email has been used to apply for a digital certificate from NDNCERT. Please keep it secret and type in to your application to finish the certificiate issuance process. If you do not know what is going on, please ignore the message.
+HTML_TEMPLATE = <html><head></head><body><p><b>Your PIN code: {0} from NDNCERT CA {1}. Certificate Name: {2}.</b></p><p>Your email has been used to apply for a digital certificate from NDNCERT. Please keep it secret and type in to your application to finish the certificiate issuance process. If you do not know what is going on, please ignore the message.</p><p>Sincerely,<br/>NDN Testbed NDNCERT robot</p>
\ No newline at end of file