Drop reread_partition_table binary

Fails to build against recent fs.h versions:

| In file included from reread_partition_table.c:12:0:
| /usr/include/linux/fs.h:366:23: error: expected '=', ',', ';', 'asm' or '__attribute__' before '__kernel_rwf_t'
|  typedef int __bitwise __kernel_rwf_t;
|                        ^~~~~~~~~~~~~~
| make[1]: *** [Makefile:24: reread_partition_table] Error 1

It's not worth any further work, partprobe(8) does the
job as well and is maintained.