Small fix on oq plot_sites [skip CI]
Small fix on oq plot_sites [skip CI]


Former-commit-id: 32668534c76399a5f857e3ec019db13458d7cbea [formerly 9b90dc0837e5443d7e8191817c7000d91a7c1166]
Former-commit-id: 8575d9b5c1a922d5769062182874c423fa08a0d6
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine