Run samples through upgrade and fix accumulated breakages:
*-centos6-*: After 2.12.2 retirement, the samples selected most recent
glibc (2.34) which also forced kernels 3.2+. Revert to 2.12.1 and
2.6.32.71, respectively. Interestingly, 2.12.1 was marked as being used
in CentOS6, but the samples selected 2.12.2. Anyway, CentOS6 is EOL now
and glibc 2.12 is going to be marked obsolete, and retired soon.
arc-*: Make TARGET_VENDOR match the sample's name; otherwise `ct-ng
saveconfig` places the config file into a different location.
Fix 'savedefconfig' which was not saving the configuration file version
(CT_VCHECK was set to 'load' after CT_LoadConfig call).
Signed-off-by: Alexey Neyman <stilor@att.net>
