Fix possible segfault in mlt_multitrack_count()
Fix possible segfault in mlt_multitrack_count()

xzhavilla/mlt,j-b-m/mlt,siddharudh/mlt,j-b-m/mlt,xzhavilla/mlt,siddharudh/mlt,mltframework/mlt,j-b-m/mlt,j-b-m/mlt,mltframework/mlt,xzhavilla/mlt,xzhavilla/mlt,xzhavilla/mlt,j-b-m/mlt,siddharudh/mlt,mltframework/mlt,j-b-m/mlt,mltframework/mlt,siddharudh/mlt,xzhavilla/mlt,siddharudh/mlt,xzhavilla/mlt,j-b-m/mlt,mltframework/mlt,mltframework/mlt,xzhavilla/mlt,mltframework/mlt,j-b-m/mlt,siddharudh/mlt,mltframework/mlt,mltframework/mlt,xzhavilla/mlt,j-b-m/mlt,siddharudh/mlt,siddharudh/mlt,mltframework/mlt,siddharudh/mlt,j-b-m/mlt