*: normalize versions of pexpect

jupyter-py2 used an old version not py3 compatible
pygolang/test used the same version as in stack/slapos.cfg

component/jupyter-py2/buildout.cfg

@@ -79,7 +79,6 @@ tornado = 4.4.2
 nbconvert = 4.1.0
 pathlib2 = 2.2.1
 patsy = 0.4.1
-pexpect = 4.2.1
 scandir = 1.5
 wcwidth = 0.1.7
 jupyter-console = 5.1.0

component/pygolang/test.cfg

@@ -56,6 +56,5 @@ simplegeneric = 0.8.1
 Pygments = 2.5.2
 prompt-toolkit = 1.0.18
 pickleshare = 0.7.5
-pexpect = 4.8.0
 backports.shutil-get-terminal-size = 1.0.0
 ptyprocess = 0.6.0