do not trial and error on parsing Gem::Specification via yaml
do not trial and error on parsing Gem::Specification via yaml

when installing via the command line any "exception" seems to get registered and will
let the install fail at the end - even if this exception was rescued.

fixes https://github.com/jruby/jruby/issues/2910 and https://github.com/tenderlove/psych/issues/234

torquebox/maven-tools,torquebox/maven-tools