Update example code

Author: pietern

intermediate_source/dist_tuto.rst

@@ -48,7 +48,7 @@ the following template.
         """ Distributed function to be implemented later. """
         pass
 
-    def init_process(rank, size, fn, backend='tcp'):
+    def init_process(rank, size, fn, backend='gloo'):
         """ Initialize the distributed environment. """
         os.environ['MASTER_ADDR'] = '127.0.0.1'
         os.environ['MASTER_PORT'] = '29500'
@@ -74,10 +74,8 @@ function.
 
 Let's have a look at the ``init_process`` function. It ensures that
 every process will be able to coordinate through a master, using the
-same ip address and port. Note that we used the TCP backend, but we
-could have used
-`MPI <https://en.wikipedia.org/wiki/Message_Passing_Interface>`__ or
-`Gloo <https://github.com/facebookincubator/gloo>`__ instead. (c.f.
+same ip address and port. Note that we used the ``gloo`` backend but
+other backends are available. (c.f.
 `Section 5.1 <#communication-backends>`__) We will go over the magic
 happening in ``dist.init_process_group`` at the end of this tutorial,
 but it essentially allows processes to communicate with each other by