Remove accidentally tracked files and unset executable flag

[e-kwsm]

Summary

Subject says it all.

Checklist

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[mkhorton]

Good catch @e-kwsm, thank you

[coveralls]

Coverage decreased (-0.6%) to 83.112% when pulling 23c0e07 on e-kwsm:chmod-x into 9276567 on materialsproject:master.