Certain drivers always need an 'emulator' specified in the XML (qemu and lxc
at least). Store this info in capabilities.

We will eventually use this to move default emulator handling out of
drivers and into domain_conf.*

Done with these commands:
git grep -l Local.variab|xargs \
  perl -0x3b -pi -e 's,\n+/\*\n \* vim:(.|\n)*,\n,'

git grep -l Local.variab|xargs \
  perl -0x3b -pi -e 's,\n+/\*\n \* Local variables:\n(.|\n)*,\n,'

  problem when generating the capabilities in the test driver.
Daniel

* src/capabilities.c (virCapabilitiesFree): Free host.migrateTrans.
(virCapabilitiesFreeGuest): Free arch.name member.

* src/capabilities.c (virCapabilitiesFreeGuestDomain): Free dom->type.
(virCapabilitiesAddGuestDomain): Remove duplicate strdup stmt.

* src/capabilities.c: Include <config.h> from the .c file,
* src/capabilities.h: ... not from the .h file.