Updates the name of the SNPs using Plink.

def renameSNPs(inPrefix, updateFileName, outPrefix):
    """Updates the name of the SNPs using Plink."""
    plinkCommand = ["plink", "--noweb", "--bfile", inPrefix, "--update-map",
                    updateFileName, "--update-name", "--make-bed", "--out",
                    outPrefix]
    runCommand(plinkCommand)