Fix version comparison for SUSE Linux Enterprise 12

The version comparison introduced in
I5152f2585c3d4d18853988d6290039d6b1713b99 was broken, because it tried
to use bash's -lt operator for floating point comparison, but bash
only supports integer arithmetic.

So instead use devstack's vercmp() function.

Change-Id: I8aac71c5bb6c2e82479d62831ea0672ba6a9a534
1 file changed