add error checking in mk_restarts executables

[weiyuan-jiang]

This PR addresses issue #464 . @gmao-jkolassa , Would you please help test this branch with regrid.pl. ( catch, catchcnclm40, catchcnclm45, maybe landice)

[gmao-jkolassa]

Thanks @weiyuan-jiang! I'll go ahead and test this for all the cases you mentioned.

[gmao-jkolassa]

I tested this and it works for catch, catchcn and landice.

[gmao-jkolassa]

@mathomp4 When running this for catch only there is still an error message that appears, which does not impact the results.
The error message is:
Use of uninitialized value $cnlist[0] in concatenation (.) or string at /discover/nobackup/jkolassa/regrid_test/GEOSgcm/install/bin//regrid.pl line 2766, <STDIN> line 6.
@weiyuan-jiang has a fix for it by changing some lines in regrid.pl, but since this would involve another GMAO_Shared PR we were wondering whether to put that in now or wait until another GMAO_Shared PR comes along (since as I said this does not actually impact the results for catch or catchcn).

What do you think?

[weiyuan-jiang]

@sdrabenh Scott, this branch has been tested and is ready to merge. Thanks