Fixing test to not rely on screencast style admonition

Author: weaverryan

tests/fixtures/expected/blocks/directives/admonition.html

@@ -1,5 +1,5 @@
-<div class="admonition admonition-default screencast_class">
+<div class="admonition admonition-default some_admonition_class">
     <p class="admonition-title">
-        <span>Screencast</span>
-    </p><p>Do you prefer video tutorials? Check out the the screencasts.</p>
+        <span>Some Admonition</span>
+    </p><p>Do you prefer admonitions? Well then... enjoy this one!</p>
 </div>

tests/fixtures/source/blocks/directives/admonition.rst

@@ -1,4 +1,4 @@
-.. admonition:: Screencast
-    :class: screencast_class
+.. admonition:: Some Admonition
+    :class: some_admonition_class
 
-    Do you prefer video tutorials? Check out the the screencasts.
+    Do you prefer admonitions? Well then... enjoy this one!