Errors should be soft warnings unless it will really break import of json/yaml

[whowutwut]

If this is missing, provide a way to bypass:

[root@c660csm01 xcat_clusters]# xcat-inventory import -f ./osimage/rhels/ist.redhat-alt.perf.custom.install.DF.osimage.yaml
Importing object: ist.redhat-alt.perf.custom.install.DF
Error: no column 'environvar' in table osimage, might caused by mismatch between schema version and xCAT version!

[whowutwut]

@immarvin I was able to resolve this by updating xCAT to the latest devel build for 2.14.2... This seems to now indicate that we MUST be in sync between xcat-inventory and xcat-core. I'm not sure I really like this dependency.. If we do things like this, we might as well ship this in xcat-core...

Otherwise it does not mean this xcat-inventory tool is generic enough... Could we simply print a warning message if the level of xCAT is not updated and recommend they update xCAT? But continue with the import of the osimages.