Install wordrank in docker

[parulsethi]

The dockerfile currently doesn't install wordrank which is one of the gensim's dependency.

The problem is to configure OpenMPI (a wordrank dependency) to have multithreading enabled. OpenMPI is installed as part of libboost-all-dev in dockerfile.

Thread configuration can be checked by running ompi_info | grep Thread:

Expected Result:

Thread support: posix (MPI_THREAD_MULTIPLE: yes, OPAL support: yes, OMPI progress: no, ORTE progress: yes, Event lib: yes)

Actual Result:

Thread support: posix (MPI_THREAD_MULTIPLE: no, OPAL support: yes, OMPI progress: no, ORTE progress: yes, Event lib: yes)

Only MPI_THREAD_MULTIPLE is relevant for our purpose which should equal to yes.