v2v: Rename module Output_RHEV to Output_rhev.

This is just code refactoring, and has no functional change to the
program.
v2v: Remove unused struct (Types.output_rhev_params).
v2v: Move some utility functions into Lib_ovf module.

This is just code refactoring and has no functional effect.
v2v: Split off -o vdsm mode from -o rhev (RHBZ#1140156).

-o rhev: This is "traditional" output to a RHEV-M Export Storage Domain.
It requires no cooperation from RHEV itself, and in all other respects
works the same way as old virt-v2v did.

-o vdsm: This is the new mode which requires VDSM cooperation.  VDSM
manages the conversion, creating the directories, suggesting UUIDs,
and cleaning up on failure.  This allows direct import into a Data
Domain.

The --rhev* command arguments now only apply to -o vdsm, and therefore
have been renamed to --vdsm*

The --vmtype command line argument may be used with -o rhev or -o vdsm.
Version 1.27.43.