Update gitdb to 4.0.1, gitdb2 to 4.0.2

The gitdb 4.0.0 release and gitdb2 4.0.1 release has been deleted from
PyPi and (if I'm reading [1] correctly, which is a big *if*) has been
replaced with 4.0.1 and 4.0.2 respectively.

  gitdb v4.0.1 and gitdb2 v4.0.2 should be functionally equivalent to
  gitdb2 v3.0.3 with gitdb v4.0.2 simply installing gitdb >= 4.0.1 and
  with gitdb v4.0.1 requiring smmap rather than smmap2
  (gitpython-developers/smmap#44).

[1] gitpython-developers/gitdb#59

Change-Id: I268fb7e1dc753c82983736572b3df2f152f8cf51

Author: ianw

upper-constraints.txt

@@ -428,8 +428,8 @@ oslo.vmware===2.35.0;python_version=='2.7'
 oslo.vmware===3.0.0;python_version=='3.6'
 oslo.vmware===3.0.0;python_version=='3.7'
 sqlalchemy-migrate===0.13.0
-gitdb===4.0.0;python_version=='3.6'
-gitdb===4.0.0;python_version=='3.7'
+gitdb===4.0.1;python_version=='3.6'
+gitdb===4.0.1;python_version=='3.7'
 python-monascaclient===1.16.0;python_version=='2.7'
 python-monascaclient===2.0.0;python_version=='3.6'
 python-monascaclient===2.0.0;python_version=='3.7'
@@ -773,8 +773,8 @@ oslo.utils===4.0.0;python_version=='3.6'
 oslo.utils===4.0.0;python_version=='3.7'
 python-editor===1.0.4
 gitdb2===2.0.6;python_version=='2.7'
-gitdb2===4.0.1;python_version=='3.6'
-gitdb2===4.0.1;python_version=='3.7'
+gitdb2===4.0.2;python_version=='3.6'
+gitdb2===4.0.2;python_version=='3.7'
 requests-kerberos===0.12.0
 itsdangerous===1.1.0
 XStatic-jquery-ui===1.12.1.1