XenAPI: Use GUEST_PASSWORD when installing DomU

We know what the GUEST_PASSWORD will be, so set it during DomU
installation; therefore if the installation fails for any reason
we have a correct GUEST_PASSWORD set rather than the obscure and
undocumented 'r00tme'

Change-Id: I684646a74f2cede43667a40556e247955e042ae4
diff --git a/tools/xen/install_os_domU.sh b/tools/xen/install_os_domU.sh
index 44e8dc1..f1cf547 100755
--- a/tools/xen/install_os_domU.sh
+++ b/tools/xen/install_os_domU.sh
@@ -207,6 +207,8 @@
             -e "s,\(d-i mirror/http/hostname string\).*,\1 $UBUNTU_INST_HTTP_HOSTNAME,g" \
             -e "s,\(d-i mirror/http/directory string\).*,\1 $UBUNTU_INST_HTTP_DIRECTORY,g" \
             -e "s,\(d-i mirror/http/proxy string\).*,\1 $UBUNTU_INST_HTTP_PROXY,g" \
+            -e "s,\(d-i passwd/root-password password\).*,\1 $GUEST_PASSWORD,g" \
+            -e "s,\(d-i passwd/root-password-again password\).*,\1 $GUEST_PASSWORD,g" \
             -i "${HTTP_SERVER_LOCATION}/devstackubuntupreseed.cfg"
     fi