bitbake: toaster: modified list of dependencies

Removed dependency to argparse and wsgiref as they're in
standard python library.

wsgiref crashes during installation with python 3 as it's not
compatible with python 3.

Added dependency to pytz as it's used in the toaster code.

(Bitbake rev: 46f185afaaef74c566eec6d8fc1edc68a3b96b32)

Signed-off-by: Ed Bartosh <ed.bartosh@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/toaster-requirements.txt

@@ -1,4 +1,3 @@
 Django>1.8,<1.9
-argparse==1.2.1
-wsgiref==0.1.2
 beautifulsoup4>=4.4.0
+pytz