ARROW-7817: [CI] macOS R autobrew nightly failed on installing depend…

…ency from source

Closes #6398 from nealrichardson/autobrew-ci-robustness and squashes the following commits:

56cb572 <Neal Richardson> Two fixes for package dependency installation failure

Authored-by: Neal Richardson <neal.p.richardson@gmail.com>
Signed-off-by: Sutou Kouhei <kou@clear-code.com>

dev/tasks/homebrew-formulae/travis.osx.r.yml

@@ -42,7 +42,8 @@ before_install:
 - cd arrow/r
 # Put the formula inside r/ so that it's included in the package build
 - cp ../dev/tasks/homebrew-formulae/autobrew/apache-arrow.rb tools/apache-arrow.rb
-before_script:
+# Always use binary packages
+- echo 'options(install.packages.check.source = "no")' >> $R_PROFILE
 # Hack for old macOS (10.11)
 # See https://travis-ci.community/t/library-developer-commandlinetools-sdks-macosx-sdk-missing-on-el-capitain/3213/3
 - sed -i.bak 's/-isysroot /-I/g' $(R RHOME)/etc/Makeconf