dummy .jshintrc to ensure defaults

Due to how Wikimedia Jenkins is setup, whenever the jshintrc is missing,
it will end up using the one from integration/docroot.git.  Creating an
empty .jshintrc file ensure we use default settings.

See bug 47260  Jenkins: repositories missing a .jshintrc file are failing

Change-Id: I6f9debc8d39f2e3770b102c9cc2aea83e7fbd727
jshint: two trivial errors in banner_screenshot

banner_screenshot/rasterize.js: line 13, col 1, Mixed spaces and tabs.
banner_screenshot/rasterize.js: line 14, col 7, Missing semicolon.

Change-Id: I7bbfbb626d457fa83b18ab14748471f7ca23c168