Removed unnecessary files from `mruby-sleep`; #4702

mrbgems/mruby-sleep/.gitignore

-/mruby
-
-*.so
-*.a
\ No newline at end of file

mrbgems/mruby-sleep/.travis.yml

-dist: trusty
-
-language: c
-compiler:
-  - gcc
-  - clang
-env:
-  - MRUBY_VERSION=1.2.0
-  - MRUBY_VERSION=master
-matrix:
-  allow_failures:
-    - env: MRUBY_VERSION=master
-branches:
-  only:
-    - master
-addons:
-  apt:
-    packages:
-      - rake
-      - bison
-      - git
-      - gperf
-      # - aclocal
-      # - automake
-      # - autoconf
-      # - autotools-dev
-
-script:
-  - rake test
\ No newline at end of file

mrbgems/mruby-sleep/.travis_build_config.rb

-MRuby::Build.new do |conf|
-  toolchain :gcc
-  conf.gembox 'default'
-  conf.gem '../mruby-sleep'
-  conf.enable_test
-end