Use our own python3 distribution to build on Travis
Use our own python3 distribution to build on Travis


Former-commit-id: ce9ba0e2424741079e3f36118866000aef0e998d [formerly 34bd03e337e7dccb3c9a08867d73adbf682cca3e]
Former-commit-id: 0efc3e5a64500b498df4dd878aa209df29920265
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine