Installation of `remotes` package fails in xenial build

I have a xenial job that errored because the package remotes failed to install. This package is not a dependency of my package but I see that it is used to download and install packages stored in Github etc. The previous version of my package built successfully on xenial so I am not sure what is causing this error.

@jeroen @jimhester

The issue was caused by my having set the PATH variable in .Renviron. I resolved it by adding this file to .gitignore.