python: adding missing runtime dependency python-io to python-pprint

When trying to import python-pprint on a minimal image, it reports that
the cStringIO python module is missing.
This is provided with python-io, so we add python-io as runtime
dependency.

The complete observed trace was:

Python 2.7.3 (default, Apr  4 2013, 07:45:36)
[GCC 4.7.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import pprint
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/lib/python2.7/pprint.py", line 40, in <module>
    from cStringIO import StringIO as _StringIO
ImportError: No module named cStringIO

(From OE-Core rev: abe7bf9992e298f1b53e790eee7b064a9e4e8589)

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@oss.bmw-carit.de>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/python/python-2.7-manifest.inc

@@ -175,7 +175,7 @@ RDEPENDS_${PN}-pkgutil="${PN}-core"
 FILES_${PN}-pkgutil="${libdir}/python2.7/pkgutil.* "
 
 DESCRIPTION_${PN}-pprint="Python Pretty-Print Support"
-RDEPENDS_${PN}-pprint="${PN}-core"
+RDEPENDS_${PN}-pprint="${PN}-core ${PN}-io"
 FILES_${PN}-pprint="${libdir}/python2.7/pprint.* "
 
 DESCRIPTION_${PN}-profile="Python Basic Profiling Support"

scripts/contrib/python/generate-manifest-2.7.py

@@ -319,7 +319,7 @@ if __name__ == "__main__":
     m.addPackage( "${PN}-pkgutil", "Python Package Extension Utility Support", "${PN}-core",
     "pkgutil.*")
 
-    m.addPackage( "${PN}-pprint", "Python Pretty-Print Support", "${PN}-core",
+    m.addPackage( "${PN}-pprint", "Python Pretty-Print Support", "${PN}-core ${PN}-io",
     "pprint.*" )
 
     m.addPackage( "${PN}-profile", "Python Basic Profiling Support", "${PN}-core ${PN}-textutils",