We can't build sendrecv_gemm_bench without blas

mpi/tests/Makefile.am

@@ -138,9 +138,13 @@ starpu_mpi_TESTS +=				\
 	user_defined_datatype			\
 	early_stuff				\
 	sendrecv_bench				\
-	sendrecv_gemm_bench			\
 	sendrecv_parallel_tasks_bench
 
+if !NO_BLAS_LIB
+starpu_mpi_TESTS +=				\
+	sendrecv_gemm_bench
+endif
+
 if !STARPU_SIMGRID
 # missing support in simgrid
 starpu_mpi_TESTS +=				\