pin pip version to 1.5.6 for python 3.1 (fixes #351)

plugins/python-build/share/python-build/3.1.3

@@ -1,3 +1,4 @@
 #require_gcc
 install_package "readline-6.3" "http://ftpmirror.gnu.org/readline/readline-6.3.tar.gz#56ba6071b9462f980c5a72ab0023893b65ba6debb4eeb475d7a563dc65cafd43" standard --if has_broken_mac_readline
-install_package "Python-3.1.3" "http://python.org/ftp/python/3.1.3/Python-3.1.3.tgz#6311823aeda8be6a7a2b67caaeff48abce6626c9940ba7ed81f9c978666a36bd" ldflags_dirs standard verify_py31 ensurepip
+install_package "Python-3.1.3" "http://python.org/ftp/python/3.1.3/Python-3.1.3.tgz#6311823aeda8be6a7a2b67caaeff48abce6626c9940ba7ed81f9c978666a36bd" ldflags_dirs standard verify_py31 ez_setup
+install_package "pip-1.5.6" "https://pypi.python.org/packages/source/p/pip/pip-1.5.6.tar.gz#b1a4ae66baf21b7eb05a5e4f37c50c2706fa28ea1f8780ce8efe14dcd9f1726c" python

plugins/python-build/share/python-build/3.1.4

@@ -1,3 +1,4 @@
 #require_gcc
 install_package "readline-6.3" "http://ftpmirror.gnu.org/readline/readline-6.3.tar.gz#56ba6071b9462f980c5a72ab0023893b65ba6debb4eeb475d7a563dc65cafd43" standard --if has_broken_mac_readline
-install_package "Python-3.1.4" "http://python.org/ftp/python/3.1.4/Python-3.1.4.tgz#fadc05ea6d05360cff189944a85ecd2180bbc308784d168b350450e70bbdd846" ldflags_dirs standard verify_py31 ensurepip
+install_package "Python-3.1.4" "http://python.org/ftp/python/3.1.4/Python-3.1.4.tgz#fadc05ea6d05360cff189944a85ecd2180bbc308784d168b350450e70bbdd846" ldflags_dirs standard verify_py31 ez_setup
+install_package "pip-1.5.6" "https://pypi.python.org/packages/source/p/pip/pip-1.5.6.tar.gz#b1a4ae66baf21b7eb05a5e4f37c50c2706fa28ea1f8780ce8efe14dcd9f1726c" python