Task failure doesnt include any backtrace

[byxorna]

When a task fails, no backtrace/line number is printed. This makes debugging failures in tasks kind of an annoying task. For example:

ProvisionFormatDisks :: run #3 caused error: undefined local variable or method `n' for Genesis::Framework::Tasks::ProvisionFormatDisks:Class

Would be useful for the runner to print the backtrace, filename, and line number for the exception, so we can at least see what happened in the genesis logs.