Fix for commented dmidecode output

This patch fixes the problem that on some system dmidecode prints out warning information as commented text. For example:

    [user@system ~]# dmidecode -s system-manufacturer
    # SMBIOS implementations newer than version 2.6 are not
    # fully supported by this version of dmidecode.
    HP

So we remove all commented lines from the output.
Merge pull request #4220 from dagwieers/setup-dmidecode-fix

Fix for commented dmidecode output