make lint is disabled on vsphere package

[jvinod]

make lint fails on vsphere package

/vsphere/vsphere_util.go:21:6: type name will be used as vsphere.VSphereConfig by other packages, and that stutters; consider calling this Config
./vsphere/vsphere_util.go:41:6: type name will be used as vsphere.VSphereInstance by other packages, and that stutters; consider calling this Instance
Makefile:32: recipe for target 'lint' failed