Fix merge error new_block_len -> block_len in whole.c.
Fix merge error new_block_len -> block_len in whole.c.

Note block_len is what is used in librsync.h for this function.

dbaarda/librsync,dbaarda/librsync,sourcefrog/librsync,sourcefrog/librsync,librsync/librsync,sourcefrog/librsync,librsync/librsync,librsync/librsync,dbaarda/librsync,dbaarda/librsync,sourcefrog/librsync,librsync/librsync