bitbake: bitbake: Update logger.warn() -> logger.warning()

python deprecated logger.warn() in favour of logger.warning(). This is only
used in bitbake code so we may as well just translate everything to avoid
warnings under python 3. Its safe for python 2.7.

(Bitbake rev: 676a5f592e8507e81b8f748d58acfea7572f8796)

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

bitbake/lib/bb/build.py

@@ -172,7 +172,7 @@ def exec_func(func, d, dirs = None, pythonexception=False):
     body = d.getVar(func, False)
     if not body:
         if body is None:
-            logger.warn("Function %s doesn't exist", func)
+            logger.warning("Function %s doesn't exist", func)
         return
 
     flags = d.getVarFlags(func)