AppRun: fix lavc warnings on Tumbleweed

suppress ldd warnings:
<https://gist.github.com/MartinPulec/ae1dc6b6e0b88f3bd02bb47c1163fdf7>

when trying the the bundled libavcodec.so with system deps

Probably OK to silence - the system libva from the live OpenSUSE ISO
seem to be preloaded.

Author: MartinPulec

data/scripts/Linux-AppImage/AppRun

@@ -197,12 +197,14 @@ libavcodec.so" | grep "$1" | grep -v 'not found' | awk '{print $3}'
         AI_LIBAVCODEC_LIB=$(get_ai_lib_path libavcodec.so)
         check_libva_deps() { # check if all liva*.so satisfied from sys
                 [ -n "$1" ] || return 1
-                ! LD_TRACE_LOADED_OBJECTS=1 "$LOADER" "$1" |
+                ! LD_TRACE_LOADED_OBJECTS=1 "$LOADER" "$1" 2>/dev/null |
                         grep -q 'libva.*not found'
         }
         check_libva_deps "$AI_LIBAVCODEC_LIB" && check_libva_deps \
                 "$(get_ai_lib_path libavutil.so)" || return 1
-        LIBVA_LIB=$(LD_TRACE_LOADED_OBJECTS=1 "$LOADER" "$AI_LIBAVCODEC_LIB" | grep libva.so | grep -v 'not found' | awk '{print $3}')
+        LIBVA_LIB=$(LD_TRACE_LOADED_OBJECTS=1 "$LOADER" "$AI_LIBAVCODEC_LIB" \
+                2>/dev/null | grep libva.so | grep -v 'not found' |
+                awk '{print $3}')
         [ -n "$LIBVA_LIB" ] || return 1
         libva_libs=$LIBVA_LIB
         # add also libva-drm, libva-x11 if present
@@ -214,7 +216,8 @@ libavcodec.so" | grep "$1" | grep -v 'not found' | awk '{print $3}'
         done
         # preload also VDPAU
         libvdpau_lib=$(LD_TRACE_LOADED_OBJECTS=1 "$LOADER" "$AI_LIBAVCODEC_LIB"\
-                 | grep libvdpau.so | grep -v 'not found' | awk '{print $3}')
+                 2>/dev/null | grep libvdpau.so | grep -v 'not found' |
+                 awk '{print $3}')
         if [ -n "$libvdpau_lib" ]; then
                 libva_libs=$libva_libs:$libvdpau_lib
         fi