pgarchives: strip angle brackets when checking for msgid search

In some email-clients, when you copy the Message-ID to the clipboard <br /> it surrounds in (or perhaps, doesn't
strip)angle brackets.<br /> When pasting this into the mail archive search, search fails to find the message<br /> and
thishappens often enough so as to be annoying. The fix is trivial.<br /><br /> Discussion of similar problem in the
commitfestapp:<br /><br /><a class="moz-txt-link-rfc2396E"
href="mailto:CABUevExRGr+Q5gzp-9cDLOqgntsOEcM0zZYg5VkADj3Z_NKz5A@mail.gmail.com"><CABUevExRGr+Q5gzp-9cDLOqgntsOEcM0zZYg5VkADj3Z_NKz5A@mail.gmail.com></a><br
/><br/> patch attached.<br /><br /> Amir<br />