[Pkg-javascript-devel] Bug#903060: npm does not rebuild documentation: update Build-Depends: ruby-ronn -> ronn

[Helmut Grohne]

Source: npm
Version: 1.4.21+ds-2

npm does not rebuild some of its documentation since ruby-ronn got split
into ronn. The build fails to catch the error from ronn and proceeds.
Please update Build-Depends and replace ruby-ronn with just ronn as npm
uses just the command line tool.

Please also make the build fail when build commands fail.

Helmut