Remove a bunch of podcasts.

I don't find any interesting content in those podcasts.

poca.xml

@@ -12,18 +12,10 @@
     <max_number>5</max_number>
   </defaults>
   <subscriptions>
-    <subscription>
-      <url>https://feeds.twit.tv/floss.xml</url>
-      <title>Floss Weekly</title>
-    </subscription>
     <subscription>
       <title>Bad Voltage</title>
       <url>https://www.badvoltage.org/feed/mp3/</url>
     </subscription>
-    <subscription>
-      <title>BSD Now</title>
-      <url>https://www.bsdnow.tv/rss</url>
-    </subscription>
     <subscription>
       <title>bsdtalk</title>
       <url>http://feeds.feedburner.com/Bsdtalk</url>
@@ -37,10 +29,6 @@
       <url>http://feed.nashownotes.com/rss.xml</url>
       <max_number>10</max_number>
     </subscription>
-    <subscription>
-      <title>Security Now</title>
-      <url>https://feeds.twit.tv/sn.xml</url>
-    </subscription>
     <subscription>
       <title>The Stack Overflow Podcast</title>
       <url>https://feeds.simplecast.com/XA_851k3</url>