Rename some global variables.

src/cdf.c

src/cdf_int.c

src/cdf_write.c

src/cdi_int.c

src/cdi_int.h

src/grid.c

src/iterator_grib.c

src/stream.c

src/stream_cdf_i.c

src/stream_cdf_o.c

src/stream_cgribex.c

src/stream_gribapi.c

src/taxis.c

src/varscan.c

src/vlist.c

src/vlist_var.c