buildMobileVLCKit: target the stable libvlc 3.0 branch for now

buildMobileVLCKit.sh

@@ -243,7 +243,7 @@ echo `pwd`
 
 if [ "$NONETWORK" != "yes" ]; then
     if ! [ -e vlc ]; then
-        git clone https://git.videolan.org/git/vlc.git vlc
+        git clone https://git.videolan.org/git/vlc/vlc-3.0.git vlc
         info "Applying patches to vlc.git"
         cd vlc
         git checkout -B localBranch ${TESTEDHASH}