Revert "Update docs and example config for requiretty + pipelining change"

This reverts commit f873cc0fb5.

Reverting pipelining change for now due to hard to pin down bugs: #13410  #13411

docsite/rst/intro_configuration.rst

@@ -800,21 +800,14 @@ pipelining
 
 Enabling pipelining reduces the number of SSH operations required to
 execute a module on the remote server, by executing many ansible modules without actual file transfer. 
-This can result in a very significant performance improvement when enabled.
-As of Ansible 2.1.0 this option is enabled by default.
+This can result in a very significant performance improvement when enabled, however when using "sudo:" operations you must
+first disable 'requiretty' in /etc/sudoers on all managed hosts.
 
-In previous versions, this option was disabled because of a bad interaction
-with some sudo configurations.  If sudo was configured to 'requiretty' for
-operation then pipelining would not work and ansible would fail to connect
-properly.  This could be remedied by removing 'requiretty' in /etc/sudoers on
-all managed hosts.
+By default, this option is disabled to preserve compatibility with
+sudoers configurations that have requiretty (the default on many distros), but is highly
+recommended if you can enable it, eliminating the need for :doc:`playbooks_acceleration`::
 
-It is recommended to leave this option enabled.  If you are stuck with an old
-version of ansible your first choice option should be to remove requiretty
-from the sudoers configuration and only disable pipelining if you cannot do
-that.  Enabling this eliminates the need for :doc:`playbooks_acceleration`::
-
-    pipelining=True
+    pipelining=False
 
 .. _accelerate_settings:
 

examples/ansible.cfg

@@ -226,13 +226,13 @@
 
 # Enabling pipelining reduces the number of SSH operations required to 
 # execute a module on the remote server. This can result in a significant 
-# performance improvement when enabled.  It is enabled by default.
+# performance improvement when enabled, however when using "sudo:" you must 
+# first disable 'requiretty' in /etc/sudoers
 #
-# In previous versions of ansible this was defaulted to off as it was
-# incompatible with sudo's requiretty option.  Ansible 2.1 and above contain
-# a fix for that problem.
+# By default, this option is disabled to preserve compatibility with
+# sudoers configurations that have requiretty (the default on many distros).
 # 
-#pipelining = True
+#pipelining = False
 
 # if True, make ansible use scp if the connection type is ssh 
 # (default is sftp)