Revert "poky: subtree update:b23aa6b753..ad30a6d470"

This reverts commit af5e4ef732faedf66c6dc1756432e9de2ac72988.

This commit introduced openbmc/openbmc#3720 and no solution has been
forthcoming. Revert until we can get to the bottom of this.

Change-Id: I2fb0d81eb26cf3dadb2f2abdd1a1bb7a95eaf03c
diff --git a/poky/bitbake/doc/conf.py b/poky/bitbake/doc/conf.py
index 354dff3..197f275 100644
--- a/poky/bitbake/doc/conf.py
+++ b/poky/bitbake/doc/conf.py
@@ -73,13 +73,7 @@
 # The theme to use for HTML and HTML Help pages.  See the documentation for
 # a list of builtin themes.
 #
-try:
-    import sphinx_rtd_theme
-    html_theme = 'sphinx_rtd_theme'
-except ImportError:
-    sys.stderr.write("The Sphinx sphinx_rtd_theme HTML theme was not found.\
-    \nPlease make sure to install the sphinx_rtd_theme python package.\n")
-    sys.exit(1)
+html_theme = 'sphinx_rtd_theme'
 
 # Add any paths that contain custom static files (such as style sheets) here,
 # relative to this directory. They are copied after the builtin static files,