Description of problem:
This crash happened when restarting the devserver by running `make devserver` just after I reset the "SITEURL" property in pelicanconf.py to `''`

Version-Release number of selected component:
python-pelican-3.3.0-5.fc21

Additional info:
reporter:       libreport-2.3.0
cmdline:        python -m pelican.server
dso_list:       python-libs-2.7.8-7.fc21.x86_64
executable:     /usr/lib/python2.7/site-packages/pelican/server.py
runlevel:       N 5
type:           Python

Truncated backtrace:
socket.py:224:meth:error: [Errno 98] Address already in use

Traceback (most recent call last):
  File "/usr/lib64/python2.7/runpy.py", line 162, in _run_module_as_main
    "__main__", fname, loader, pkg_name)
  File "/usr/lib64/python2.7/runpy.py", line 72, in _run_code
    exec code in run_globals
  File "/usr/lib/python2.7/site-packages/pelican/server.py", line 37, in <module>
    httpd = socketserver.TCPServer(("", PORT), Handler)
  File "/usr/lib64/python2.7/SocketServer.py", line 419, in __init__
    self.server_bind()
  File "/usr/lib64/python2.7/SocketServer.py", line 430, in server_bind
    self.socket.bind(self.server_address)
  File "/usr/lib64/python2.7/socket.py", line 224, in meth
    return getattr(self._sock,name)(*args)
error: [Errno 98] Address already in use

Local variables in innermost frame:
self: <socket._socketobject object at 0x7f9a2bdb3fa0>
args: (('', 8000),)
name: 'bind'