Call sudo with -H in pip_install

Commit 7aa7699 was an incomplete
cherry pick since it missed the part that added -H to sudo pip install.

This is similar to what was added in change
If791b9b25d6a4280dab19117004184e57e78d038.

This is needed on stable/icehouse only since the change was made in
Kilo originally and backported to stable/juno.  This should fix grenade
against stable/juno changes where the 'old' side is stable/icehouse.

Change-Id: Ia52823ec2e322f78d407993010eb04adf39a242c
Closes-Bug: #1463149

Author: Matt Riedemann

functions-common

@@ -1356,7 +1356,7 @@ function pip_install {
         CMD_PIP=$DEST/.venv/bin/pip
         SUDO_PIP="env"
     else
-        SUDO_PIP="sudo"
+        SUDO_PIP="sudo -H"
         CMD_PIP=$(get_pip_command)
     fi