Add symlink to ensure pip3 can find a Python installation.

Python3 tests were failing locally because the python build was gettting
denied permission to create a hardlink between python3.4 and python3.4m in the
installs directory.  This was a problem because pip3 and other scripts look
for ${IROOT}/py3/bin/python3.4.

toolset/setup/linux/languages/python3.sh

@@ -10,6 +10,7 @@ cd Python-3.4.2
 make -j4 --quiet
 make install --quiet
 
+ln -s ${IROOT}/py3/bin/python3.4m ${IROOT}/py3/bin/python3.4
 ${IROOT}/py3/bin/python3 -m ensurepip -U
 ${IROOT}/py3/bin/pip3 install -U setuptools pip