mpiJava: call mca_base_var_register *after* MPI_Init
Thanks to Takahiro Kawashima and Siegmar Gross for pointing this issue

(cherry picked from commit a16c1e44189366fbc8e967769e050f517a40f3f8)
Merge pull request #62 from jsquyres/pr/java-mca-var-register-fix

mpiJava: call mca_base_var_register *after* MPI_Init