Clarification on absence of master branch

[lgatto]

After the command showing how to clone the newly imported repository, there is this sentence

This is needed because the imported repository doesn't have a master branch.

which I find a bit unclear. If the this refers to explicitly naming the branch, I would suggest rephrasing as follows:

The -b gh-pages is needed because the imported repository doesn't have a default master branch.

I can send a PR if useful.