The `-i` flag causes a problem when a cross compilation happens because
it attempts to build files in GOROOT which is located in a directory
that is not writable by the build user. This same problem exists for
when the `-tags` are changed like adding `-tags assets` in the `all`
build that runs on the master branch.
This removes `-i` because, in the latest go release, the `-i` flag
doesn't actually do anything useful since there is another build cache
that the results are placed in regardless of whether `-i` is used.
This fixes the build on master so that `make all` and `make nightly`
will function properly.
Edd Robinson
Ben Johnson
Jonathan A. Sternberg
Stuart Carnie
Christopher Wolff
Nathaniel Cook