bitbake: doc/conf.py: add missing import sys

Due to the calls to sys.stderr.write() and sys.exit() in exception
handling in case of sphinx_rtd_theme not being installed, the
following exception is raised by Python due to the fact that sys
module not being imported.

(Bitbake rev: 5ddf0e5bee0de59d07295fc5693e20b1a0380fde)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/doc/conf.py

@@ -14,6 +14,7 @@
 # import sys
 # sys.path.insert(0, os.path.abspath('.'))
 
+import sys
 import datetime
 
 current_version = "dev"