[opensuse] add python-xml to general deps list

the python-xml is a subpackage from the standard cpython package that
that contains elementtree and other bits that are needed almost
everywhere in OpenStack but isn't installed on a absolutely minimal
openSUSE Leap installation. This package doesn't exist on pip but
is a SUSE only invention, so just treat it similar to a bindep.

Change-Id: I82887c2e6895740d1b16d1269574519450ca783e
diff --git a/files/rpms-suse/general b/files/rpms-suse/general
index 3b19071..1044c25 100644
--- a/files/rpms-suse/general
+++ b/files/rpms-suse/general
@@ -21,6 +21,7 @@
 psmisc
 python-cmd2 # dist:opensuse-12.3
 python-devel  # pyOpenSSL
+python-xml
 screen
 tar
 tcpdump