OpenMP, Fortran: Bugfix for omp_set_num_teams.

This patch fixes a small bug in the omp_set_num_teams implementation.

libgomp/ChangeLog:

	* fortran.c (omp_set_num_teams_8_): Call omp_set_num_teams instead of
	omp_set_max_active_levels.
	* testsuite/libgomp.fortran/icv-8.f90: New test.