Provide consistent way for setting page description

Issue #976
Signed-off-by: Michal Čihař <michal@cihar.com>

weblate/html/base.html

@@ -13,9 +13,7 @@
   <meta name="copyright" content="Copyright &copy; 2003 - {{ current_year }} Michal Čihař" />
 
   <title>{% include "title.html" %}</title>
-{% if description %}
   <meta name="description" content="{{ description }}" />
-{% endif %}
 
 {% compress css %}
   <link rel="stylesheet" type="text/css" href="{% static 'bootstrap/css/bootstrap.css' %}" />
@@ -53,11 +51,7 @@
   <meta name="viewport" content="width=device-width, initial-scale=1" />
   <meta property="og:site_name" content="{% if site_title %}{{ site_title }}{% else %}Weblate{% endif %}" />
   <meta property="og:title" content="{% if title %}{{ title }}{% else %}{% if object %}{{ object }}{% else %}{% if page_profile %}{{ page_profile.get_user_name }}{% else %}{% if site_title %}{{ site_title }}{% else %}Weblate{% endif %}{% endif %}{% endif %}{% endif %}" />
-  {% if offer_hosting %}
-  <meta property="og:description" content="{% trans "Hosted Weblate, the place to translate your software project." %}" />
-  {% else %}
-  <meta property="og:description" content="{% trans "This site runs Weblate for translating various software projects." %}" />
-  {% endif %}
+  <meta property="og:description" content="{{ description }}" />
 
 {% block extra_meta %}
 {% endblock %}

weblate/trans/context_processors.py

@@ -20,6 +20,8 @@
 
 from datetime import datetime
 
+from django.utils.translation import ugettext as _
+
 import weblate
 from weblate import appsettings
 from weblate.trans.site import get_site_url
@@ -51,8 +53,18 @@ def weblate_context(request):
             'subproject__project__name', 'subproject__name'
         ).select_related()
 
+    if appsettings.OFFER_HOSTING:
+        description = _(
+            'Hosted Weblate, the place to translate your software project.'
+        )
+    else:
+        description = _(
+            'This site runs Weblate for translating various software projects.'
+        )
+
     return {
         'version': weblate.VERSION,
+        'description': description,
 
         'weblate_url': URL_BASE % weblate.VERSION,
         'donate_url': URL_DONATE % weblate.VERSION,