Avoid Travis timeouts for OpenMPI builds on OS X

Author: eschnett

conf/travis-install-mpi.sh

@@ -20,7 +20,8 @@ case "$os" in
             openmpi)
                 # Temporarily build OpenMPI from source, since apparently our
                 # cmake doesn't know how to handle OpenMPI 1.10 yet
-                brew install openmpi --build-from-source
+                brew install openmpi --build-from-source --verbose |
+                    sed -e 's/^.*$/./'
                 ;;
             *)
                 echo "Unknown MPI implementation: $MPI_IMPL"