replaced all xrealloc with realloc in src

src/gribapi_utilities.c

src/grid.c

src/input_file.c

src/iterator_grib.c

src/namespace.c

src/pio_server.c

src/resource_handle.c

src/resource_unpack.c

src/stream_cdf.c

src/stream_cgribex.c

src/stream_ext.c

src/stream_gribapi.c

src/stream_ieg.c

src/stream_record.c

src/stream_srv.c

src/stream_var.c

src/tsteps.c

src/varscan.c

src/vlist.c

src/vlist_att.c