With the merge of [1], the way the bootstrap AIO script evaluates
the sources.list file for ubuntu was changed, which inadvertently
broke any distros using ubuntu-ports. This patch fixes the regex
to support ubuntu-ports repos.
[1] I7fab8f3c072e25fa8138c3e37d764b36d17526d6
Change-Id: I7ecd9dc130d194342e236bef42b08926f98940fd