Fix membership_admin variable

member.md

@@ -12,10 +12,10 @@ SIGMathLing has members from
 
 ## Becoming a {{site.title}} Member
 To become a {{site.title}} member you have to
-1. print, sign, scan the [NDA](/nda/) and send it to [the members admin contact](mailto:{{membership_admin}}) by e-mail
+1. print, sign, scan the [NDA](/nda/) and send it to [the members admin contact](mailto:{{site.membership_admin}}) by e-mail
 2. {{site.title}} will counter-sign file and send you the result for your files.
 3. {{site.title}} will keep the signed [NDA](/nda/) on file, sign you up for the mailing list, and give you access to the resource repositories.  
 
 ## Terminating {{site.title}} Membership
 
-To terminate {{site.title}} membership, send an e-mail to the [the members admin contact](mailto: {{membership_admin}}) clearly stating your desire to terminate you membership. {{site.title}} will unsubscribe you from the membership roster and the {{site.title}} mailing list. 
+To terminate {{site.title}} membership, send an e-mail to the [the members admin contact](mailto: {{site.membership_admin}}) clearly stating your desire to terminate you membership. {{site.title}} will unsubscribe you from the membership roster and the {{site.title}} mailing list.