patch: Don't display the '<' and '>' characters in the message-id

Fixes #54: #54
Suggested-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>

patchwork/templates/patchwork/patch.html

@@ -42,7 +42,7 @@ <h2>Details</h2>
 <table class="patchmeta">
  <tr>
   <th>Message ID</th>
-  <td>{{ patch.msgid }}</td>
+  <td>{{ patch.msgid|msgid }}</td>
  </tr>
   <tr>
    <th>State</th>

patchwork/templatetags/patch.py

@@ -19,6 +19,7 @@
 
 from django import template
 from django.utils.safestring import mark_safe
+from django.template.defaultfilters import stringfilter
 
 register = template.Library()
 
@@ -31,3 +32,9 @@ def patch_tags(patch, tag):
     title = '%d %s' % (count, tag.name)
     return mark_safe('<td class="%s"><span title="%s">%s</span></td>' %
                      (class_str, title, count_str))
+
+
+@register.filter
+@stringfilter
+def msgid(patch):
+    return patch.strip('<>')