rauc: add missing dependencies for host variant

rauc: add missing dependencies for host variant

rauc unconditionally needs OpenSSL and libglib2. Those dependencies
were properly accounted for the target variant, but not the host
variant, causing build failures. This commit adds the missing
dependencies.

Fixes:

  http://autobuild.buildroot.net/results/2695202ee3b0734430abc2db03828a45cd5e5ef5
  (host-openssl missing)

  http://autobuild.buildroot.net/results/77a5db1120bf90ccaac00cfc0a8db358cacd894c
  (host-libglib2 missing)

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>