[1.4.x] Updated obsolete links in the documentation

Backport of 8a5d1a6b93 from master.

docs/topics/email.txt

@@ -192,7 +192,7 @@ from the request's POST data, sends that to admin@example.com and redirects to
             # to get proper validation errors.
             return HttpResponse('Make sure all fields are entered and valid.')
 
-.. _Header injection: http://www.nyphp.org/phundamentals/email_header_injection.php
+.. _Header injection: http://www.nyphp.org/phundamentals/8_Preventing-Email-Header-Injection
 
 .. _emailmessage-and-smtpconnection:
 

docs/topics/http/sessions.txt

@@ -516,7 +516,7 @@ consistently by all browsers. However, when it is honored, it can be a
 useful way to mitigate the risk of client side script accessing the
 protected cookie data.
 
-.. _HTTPOnly: http://www.owasp.org/index.php/HTTPOnly
+.. _HTTPOnly: https://www.owasp.org/index.php/HTTPOnly
 
 SESSION_COOKIE_NAME
 -------------------

docs/topics/install.txt

@@ -70,7 +70,7 @@ server platforms. See the `server-arrangements wiki page`_ for specific
 installation instructions for each platform.
 
 .. _Apache: http://httpd.apache.org/
-.. _nginx: http://nginx.net/
+.. _nginx: http://nginx.org/
 .. _mod_wsgi: http://code.google.com/p/modwsgi/
 .. _server-arrangements wiki page: https://code.djangoproject.com/wiki/ServerArrangements
 

docs/topics/testing.txt

@@ -1940,7 +1940,7 @@ out the `full reference`_ for more details.
 
 .. _Selenium: http://seleniumhq.org/
 .. _selenium package: http://pypi.python.org/pypi/selenium
-.. _full reference: http://readthedocs.org/docs/selenium-python/en/latest/api.html
+.. _full reference: http://selenium-python.readthedocs.org/en/latest/api.html
 .. _Firefox: http://www.mozilla.com/firefox/
 
 .. note::