fix block for email subject on project/release removal emails

missed in review on #7071

Author: ewdurbin

warehouse/templates/email/removed-project-release/subject.txt

@@ -14,5 +14,4 @@
 
 {% extends "email/_base/subject.txt" %}
 
-{% block content %}
-{% trans project=project, release=release %}The {{ project }} release {{ release }} has been deleted.{% endtrans  %}{% endblock %}
+{% block subject %}{% trans project=project, release=release %}The {{ project }} release {{ release }} has been deleted.{% endtrans  %}{% endblock %}

warehouse/templates/email/removed-project/subject.txt

@@ -14,6 +14,4 @@
 
 {% extends "email/_base/subject.txt" %}
 
-{% block content %}
-  {% trans project=project %}The project {{ project }} has been deleted.{% endtrans %}
-{% endblock %}
+{% block subject %}{% trans project=project %}The project {{ project }} has been deleted.{% endtrans %}{% endblock %}