Fix float value in libsvm reader.
Fix float value in libsvm reader.

nemesiscodex/mockingbird,nemesiscodex/mockingbird,lazywei/mockingbird,lazywei/mockingbird,nemesiscodex/mockingbird,nemesiscodex/mockingbird,lazywei/mockingbird,lazywei/mockingbird,lazywei/mockingbird,nemesiscodex/mockingbird,lazywei/mockingbird,lazywei/mockingbird,nemesiscodex/mockingbird,nemesiscodex/mockingbird,nemesiscodex/mockingbird,lazywei/mockingbird,lazywei/mockingbird,nemesiscodex/mockingbird