[fix] - Makefile - change sed expression to be cross platform

[mur-me]

Issue

Makefile - change sed expression to be cross platform, because Macos has sed openbsd version and linux has GNU one, add git restore for the localnet configs on the explicit debug-kill

Tested on the Linux and Mac

$ make debug-ext and grep localnetBlocks internal/configs/sharding/localnet.go

	localnetBlocksPerEpoch = 64
	localnetBlocksPerEpochV2 = 64

$ make debug-kill and grep localnetBlocks internal/configs/sharding/localnet.go

        localnetBlocksPerEpoch   = 16
        localnetBlocksPerEpochV2 = 16

Before:

<!-- copy/paste 'go test -cover' result in the directory you made change -->

After:

<!-- copy/paste 'go test -cover' result in the directory you made change -->

Test/Run Logs

Operational Checklist

1. Does this PR introduce backward-incompatible changes to the on-disk data structure and/or the over-the-wire protocol?. (If no, skip to question 8.)

   YES|NO

2. Describe the migration plan.. For each flag epoch, describe what changes take place at the flag epoch, the anticipated interactions between upgraded/non-upgraded nodes, and any special operational considerations for the migration.

3. Describe how the plan was tested.

4. How much minimum baking period after the last flag epoch should we allow on Pangaea before promotion onto mainnet?

5. What are the planned flag epoch numbers and their ETAs on Pangaea?

6. What are the planned flag epoch numbers and their ETAs on mainnet?

   Note that this must be enough to cover baking period on Pangaea.

7. What should node operators know about this planned change?

8. Does this PR introduce backward-incompatible changes NOT related to on-disk data structure and/or over-the-wire protocol? (If no, continue to question 11.)

   YES|NO

9. Does the existing node.sh continue to work with this change?

10. What should node operators know about this change?

11. Does this PR introduce significant changes to the operational requirements of the node software, such as >20% increase in CPU, memory, and/or disk usage?

TODO

[sophoah]

@Frozen this one is for you, please test and approve if the change works for you.

[Frozen]

# after make debug-ext 
% grep localnetBlocks internal/configs/sharding/localnet.go


        localnetBlocksPerEpoch   = 16
        localnetBlocksPerEpochV2 = 16
        return localnetBlocksPerEpoch
        return localnetBlocksPerEpochV2

[sophoah]

@mur-me