Revert ibrowse dependency to its original repository

This patch reverts the dependency on ibrowse to v4.0.2 of its original
repository. ibrowse has received a lot of fixes since it was forked by
Opscode. The repository that mini_s3 depends on has lagged behind and even
contains an error in a format string in ibrowse.erl:

    src/ibrowse.erl:627: Warning: wrong number of arguments in format call
Replace calls to crypto functions with variants introduced in R16B

The previous variants have been deprecated and raise warnings during
the compilation process.