Use LGPL-2.1 license text
Use LGPL-2.1 license text

Even if the license reference was right, in the patch buildup
the license header of GPL got mixed where LGPL-2.1 was
intended. Fix it ASAP.

Change-Id: I15cf1a38fe56a986c69543b7d237b9fa9fee654e

lulufei/kurento-media-server,mparis/kurento-media-server,TribeMedia/kurento-media-server,shelsonjava/kurento-media-server,Kurento/kurento-media-server,mparis/kurento-media-server,lulufei/kurento-media-server,TribeMedia/kurento-media-server,todotobe1/kurento-media-server,shelsonjava/kurento-media-server,todotobe1/kurento-media-server,Kurento/kurento-media-server