MySQL: Certificate Serial Number should be 128 in length. (#704)
MySQL: Certificate Serial Number should be 128 in length. (#704)

Modified previous migration as per @lziest suggestion.

Fixes #703
drcapulet/cfssl,geligaoli/cfssl,sfurman3/cfssl,geligaoli/cfssl,cloudflare/cfssl,sfurman3/cfssl,drcapulet/cfssl,geligaoli/cfssl,cloudflare/cfssl,sfurman3/cfssl,cloudflare/cfssl,geligaoli/cfssl,drcapulet/cfssl,drcapulet/cfssl,drcapulet/cfssl,sfurman3/cfssl,sfurman3/cfssl,cloudflare/cfssl,geligaoli/cfssl