Fix setting muxer-specific options (SF-197).
Fix setting muxer-specific options (SF-197).

Patch provided by Peter Egro <pegro@users.sf.net>

j-b-m/mlt,wideioltd/mlt,xzhavilla/mlt,mltframework/mlt,wideioltd/mlt,mltframework/mlt,xzhavilla/mlt,j-b-m/mlt,wideioltd/mlt,anba8005/mlt,zzhhui/mlt,anba8005/mlt,xzhavilla/mlt,xzhavilla/mlt,j-b-m/mlt,wideioltd/mlt,zzhhui/mlt,wideioltd/mlt,siddharudh/mlt,mltframework/mlt,siddharudh/mlt,wideioltd/mlt,wideioltd/mlt,j-b-m/mlt,anba8005/mlt,j-b-m/mlt,mltframework/mlt,siddharudh/mlt,zzhhui/mlt,xzhavilla/mlt,mltframework/mlt,siddharudh/mlt,zzhhui/mlt,anba8005/mlt,zzhhui/mlt,zzhhui/mlt,siddharudh/mlt,zzhhui/mlt,j-b-m/mlt,xzhavilla/mlt,xzhavilla/mlt,siddharudh/mlt,j-b-m/mlt,wideioltd/mlt,j-b-m/mlt,wideioltd/mlt,mltframework/mlt,mltframework/mlt,anba8005/mlt,siddharudh/mlt,anba8005/mlt,anba8005/mlt,j-b-m/mlt,siddharudh/mlt,anba8005/mlt,anba8005/mlt,zzhhui/mlt,siddharudh/mlt,mltframework/mlt,zzhhui/mlt,mltframework/mlt,xzhavilla/mlt,xzhavilla/mlt,mltframework/mlt,j-b-m/mlt