Code review comment for lp:~berendt/nova/fixing_713434

From pep8:

nova/network/linux_net.py:321:1: W191 indentation contains tabs
       FLAGS.dhcp_domain,
^
    For new projects, spaces-only are strongly recommended over tabs. Most
    editors have features that make this easy to do.

    Okay: if True:\n return
    W191: if True:\n\treturn
nova/network/linux_net.py:321:1: E101 indentation contains mixed spaces and tabs
       FLAGS.dhcp_domain,
^
    Never mix tabs and spaces.

    The most popular way of indenting Python is with spaces only. The
    second-most popular way is with tabs only. Code indented with a mixture
    of tabs and spaces should be converted to using spaces exclusively. When
    invoking the Python command line interpreter with the -t option, it issues
    warnings about code that illegally mixes tabs and spaces. When using -tt
    these warnings become errors. These options are highly recommended!

    Okay: if a == 0:\n a = 1\n b = 1
    E101: if a == 0:\n a = 1\n\tb = 1
nova/network/linux_net.py:366:1: W191 indentation contains tabs
    ' --domain=%s' % FLAGS.dhcp_domain,
^
    For new projects, spaces-only are strongly recommended over tabs. Most
    editors have features that make this easy to do.

    Okay: if True:\n return
    W191: if True:\n\treturn
nova/network/linux_net.py:366:1: E101 indentation contains mixed spaces and tabs
    ' --domain=%s' % FLAGS.dhcp_domain,
^
    Never mix tabs and spaces.

    The most popular way of indenting Python is with spaces only. The
    second-most popular way is with tabs only. Code indented with a mixture
    of tabs and spaces should be converted to using spaces exclusively. When
    invoking the Python command line interpreter with the -t option, it issues
    warnings about code that illegally mixes tabs and spaces. When using -tt
    these warnings become errors. These options are highly recommended!

    Okay: if a == 0:\n a = 1\n b = 1
    E101: if a == 0:\n a = 1\n\tb = 1