Fix typo on first line of db_quota_notification_.txt

server/conf/mail/db_quota_notification_de.txt

-ME-Version: 1.0
+MIME-Version: 1.0
 Content-type: text/plain; charset=utf-8
 Content-Transfer-Encoding: 8bit
 From: {admin_mail}

server/conf/mail/db_quota_notification_en.txt

-ME-Version: 1.0
+MIME-Version: 1.0
 Content-type: text/plain; charset=utf-8
 Content-Transfer-Encoding: 8bit
 From: {admin_mail}

server/conf/mail/db_quota_notification_es.txt

-ME-Version: 1.0
+MIME-Version: 1.0
 Content-type: text/plain; charset=utf-8
 Content-Transfer-Encoding: 8bit
 From: {admin_mail}
 Reply-To: {admin_mail}
 Subject: Notificación de cuota de base de datos
 
-La base de datos {database_name} está cerca o ha superado su cuota.
+La base de datos {database_name} esta cerca o ha superado su cuota.
 
 Base de datos:		{database_name}
 Espacio usado:		{used}