python-pexpect: Fix runtime failure with ptyprocess

python-pexpect needs python-ptyprocess and this was not
specified in the .bb file.  This is fixed upstream with
python-pexpect_4.1.0, but not backported for 4.0.1, which is
the current version used in the yocto 2.1 tree.

Also, needed to backport the ptyprocess package itself.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
diff --git a/common/recipes-devtools/python/python-pexpect_4.0.1.bbappend b/common/recipes-devtools/python/python-pexpect_4.0.1.bbappend
new file mode 100644
index 0000000..25e2809
--- /dev/null
+++ b/common/recipes-devtools/python/python-pexpect_4.0.1.bbappend
@@ -0,0 +1 @@
+RDEPENDS_${PN}_append = "python-ptyprocess"