Fix service.py version parsing for SLE 11

"osrelease" on SLES 11 is in the form "11 SP3", i.e. major version, then a space, then service pack number. This means we can't just split on '.' to get the major number for comparisons. Rather we need to split on non-digit characters to handle both space-delimited and dot-delimited release formats (yuck).
Merge pull request #15064 from tserong/patch-1

Fix service.py version parsing for SLE 11