Workaround for ovfenv not working after a reboot

[kars7e]

Add a wrapper around ovfenv that checks if ovf properties are properly returned. If not, read the data from the cache stored on disk.

Fixes #754 Fixes #747

Additional fixes:

• Correctly sets the locale
• creates firstboot file so that firstboot-only scripts do not execute again
• use HOST instead of HOSTNAME as HOSTNAME is a built-in variable

Testing:

• tested in fusion 11.0.2
• tested on VMC

[kars7e]

@zjs thanks for a thorough review! I added the wrapper to sshd_permitrootlogin.sh as well.