modify lstm ouput for aggregated model
modify lstm ouput for aggregated model

using the h value of the last lstm layer as the input for aggregated model is better, and easier to converge.
slai11/youtube-8m,forwchen/yt8m,forwchen/yt8m,slai11/youtube-8m,KangHsi/youtube-8m,google/youtube-8m,slai11/youtube-8m,slai11/youtube-8m,KangHsi/youtube-8m