requirement.txt: install binary psyscopg2 wheel
requirement.txt: install binary psyscopg2 wheel

Do not rebuild psycopg2 from source, it requires the host to have all
the toolchain installed.

Signed-off-by: Paolo Bonzini <69d3ebcf5ee4e7f05a50dc23cd96655b730804b4@redhat.com>

pvital/patchew,pvital/patchew,pvital/patchew,pvital/patchew