remove unused function MPI_Abi_supported

this was something  in a very early ABI proposal which was dropped.

Signed-off-by: Howard Pritchard <howardp@lanl.gov>

Author: hppritcha

ompi/mpi/bindings/ompi_bindings/c.py

@@ -188,7 +188,6 @@ def dump_header(self):
         for sig in self.signatures:
             self.dump(f'{sig};')
         self.dump('int MPI_Abi_details(int *buflen, char *details, MPI_Info *info);')
-        self.dump('int MPI_Abi_supported(int *flag);')
         self.dump('int MPI_Abi_version(int *abi_major, int *abi_minor);')
 
         self.dump("""