[manual] Rename manage.py subscribe_new_users to process_signups.

The old name was very confusing, and this fits the convention of "the
processor for the signups" queue a la "process_user_activity".

This requires doing a

supervisorctl stop humbug-workers:humbug-events-subscribe-new-users
puppet apply

to deploy the supervisord configuration changes and properly restart
the signups queue.

(imported from commit 0ee2dad837142afa64025446e22956709771a192)

servers/puppet/modules/humbug/files/nagios3/commands.cfg

@@ -103,7 +103,7 @@ define command{
 
 define command{
         command_name    check_process_mailchimp_signups
-        command_line    /usr/lib/nagios/plugins/check_by_ssh -p $ARG1$ -l nagios -t 30 -i /var/lib/nagios/.ssh/id_rsa -H $HOSTADDRESS$ -C '/usr/lib/nagios/plugins/check_procs -u humbug -c 1:1 -a "manage.py subscribe_new_users"'
+        command_line    /usr/lib/nagios/plugins/check_by_ssh -p $ARG1$ -l nagios -t 30 -i /var/lib/nagios/.ssh/id_rsa -H $HOSTADDRESS$ -C '/usr/lib/nagios/plugins/check_procs -u humbug -c 1:1 -a "manage.py process_signups"'
 }
 
 define command{

servers/puppet/modules/humbug/files/supervisord/conf.d/humbug.conf

@@ -66,8 +66,8 @@ redirect_stderr=true           ; redirect proc stderr to stdout (default false)
 stdout_logfile=/var/log/humbug/events-user-activity.log         ; stdout log path, NONE for none; default AUTO
 directory=/home/humbug/humbug-deployments/current/
 
-[program:humbug-events-subscribe-new-users]
+[program:humbug-events-signups]
-command=python /home/humbug/humbug-deployments/current/manage.py subscribe_new_users
+command=python /home/humbug/humbug-deployments/current/manage.py process_signups
 priority=400                   ; the relative start priority (default 999)
 autostart=true                 ; start at supervisord start (default: true)
 autorestart=true               ; whether/when to restart (default: unexpected)
@@ -75,7 +75,7 @@ stopsignal=TERM                ; signal used to kill process (default TERM)
 stopwaitsecs=30                ; max num secs to wait b4 SIGKILL (default 10)
 user=humbug                    ; setuid to this UNIX account to run the program
 redirect_stderr=true           ; redirect proc stderr to stdout (default false)
-stdout_logfile=/var/log/humbug/events-subscribe-new-users.log         ; stdout log path, NONE for none; default AUTO
+stdout_logfile=/var/log/humbug/events-signups.log         ; stdout log path, NONE for none; default AUTO
 directory=/home/humbug/humbug-deployments/current/
 
 [program:humbug-events-confirmation-emails]
@@ -107,7 +107,7 @@ directory=/home/humbug/humbug-deployments/current/
 ; process groups.
 
 [group:humbug-workers]
-programs=humbug-events-user-activity,humbug-events-subscribe-new-users,humbug-events-confirmation-emails,humbug-events-missedmessage_reminders  ; each refers to 'x' in [program:x] definitions
+programs=humbug-events-user-activity,humbug-events-signups,humbug-events-confirmation-emails,humbug-events-missedmessage_reminders  ; each refers to 'x' in [program:x] definitions
 
 ; The [include] section can just contain the "files" setting.  This
 ; setting can list multiple files (separated by whitespace or