MT#16755 Export HOME env variable to workaround mr4.2.1 error

The ngcp-installer has failed, the error is:
> 2016-01-29 11:43:21: Executing sync-db:
>                      insert new rtp_interface ext=ext from config into db
> fatal: $HOME not set
> fatal: $HOME not set

It can be related to the new Jessie base AMI image we have switched,
the old one Wheezy AMI image has probably HOME defined.
While we are not sure here.

Change-Id: I3ab7dbb59f6081fb680c8447c18d29041a2f6563

ec2-create-ce

@@ -290,6 +290,10 @@ cat > "$USER_DATA_FILE" << EOF
 #!/bin/bash
 wget -O /tmp/ngcp-installer.deb http://deb.sipwise.com/spce/ngcp-installer-${NGCP_RELEASE}.deb
 dpkg -i /tmp/ngcp-installer.deb
+
+# workaround for mr4.2.1
+export HOME=/root/
+
 FORCE=yes ngcp-installer 2>&1 | tee -a /var/log/ngcp-installer-debug.log
 cp /tmp/ngcp-installer.log /var/log/ngcp-installer.log
 EOF