Drop invalid annotations in segment_info

[escorciav]

Some videos of Thumos14 are incorrectly annotated e.g. video_validation_0000364 and video_validation_0000856. In order to avoid unpleasant surprises, it's useful to drop rows of the data-frame where t-init or t-end < video-duration

idx_drop = ((df['video-duration'] < df['t-init']) | (df['video-duration'] < df['t-end'])).nonzero()[0]
df.drop(idx_drop, inplace=True)