Fix race condition

[acomodi]

There seem to be yet another race condition that causes an intermittent failure:

- 2h40m: Traceback (most recent call last):
- 2h40m:   File "/root/prjxray/prjxray/utils/bit2fasm.py", line 126, in <module>
- 2h40m:     main()
- 2h40m:   File "/root/prjxray/prjxray/utils/bit2fasm.py", line 122, in main
- 2h40m:     args.canonical)
- 2h40m:   File "/root/prjxray/prjxray/utils/bit2fasm.py", line 50, in bits_to_fasm
- 2h40m:     sort_key=grid.tile_key,
- 2h40m:   File "/root/prjxray/prjxray/third_party/fasm/fasm/output.py", line 386, in merge_and_sort
- 2h40m:     for line in model:
- 2h40m:   File "/root/prjxray/prjxray/prjxray/fasm_disassembler.py", line 131, in find_features_in_bitstream
- 2h40m:     solved_bitdata, bitdata, verbose=verbose):
- 2h40m:   File "/root/prjxray/prjxray/prjxray/fasm_disassembler.py", line 61, in find_features_in_tile
- 2h40m:     tile_segbits = self.grid.get_tile_segbits_at_tilename(tile_name)
- 2h40m:   File "/root/prjxray/prjxray/prjxray/grid.py", line 149, in get_tile_segbits_at_tilename
- 2h40m:     return self.db.get_tile_segbits(gridinfo.tile_type)
- 2h40m:   File "/root/prjxray/prjxray/prjxray/db.py", line 218, in get_tile_segbits
- 2h40m:     self.tile_types[tile_type.upper()])
- 2h40m:   File "/root/prjxray/prjxray/prjxray/tile_segbits.py", line 95, in __init__
- 2h40m:     self.segbits[BlockType.CLB_IO_CLK] = read_segbits(f)
- 2h40m:   File "/root/prjxray/prjxray/prjxray/tile_segbits.py", line 75, in read_segbits
- 2h40m:     segbits[parts[0]] = [parsebit(val) for val in parts[1:]]
- 2h40m:   File "/root/prjxray/prjxray/prjxray/tile_segbits.py", line 75, in <listcomp>
- 2h40m:     segbits[parts[0]] = [parsebit(val) for val in parts[1:]]
- 2h40m:   File "/root/prjxray/prjxray/prjxray/tile_segbits.py", line 56, in parsebit
- 2h40m:     word_bit=int(word_bit_n),
- 2h40m: ValueError: invalid literal for int() with base 10: '1END2'

The above error is most probably a result of a .db file corruption from another process while it is being read to access its information.