Correct error in build.sh

scripts/build.sh

@@ -119,17 +119,17 @@ for target in "${TARGETS[@]}" ; do
 	merge+=("$sourcedir/manifest.merge.json")
     [ "$origdir" -a -f "$origdir/manifest.merge.json" ] && \
 	merge+=("$origdir/manifest.merge.json")
-    [ "$beta" -a "$sourcedir/manifest.beta.merge.json" ] && \
+    [ "$beta" -a -f "$sourcedir/manifest.beta.merge.json" ] && \
 	merge+=("$sourcedir/manifest.beta.merge.json")
-    [ "$origdir" -a "$beta" -a "$sourcedir/manifest.beta.merge.json" ] && \
+    [ "$origdir" -a "$beta" -a -f "$sourcedir/manifest.beta.merge.json" ] && \
 	merge+=("$origdir/manifest.beta.merge.json")
 
     override=()
     [ "$origdir" -a -f "$origdir/manifest.override.json" ] && \
 	override+=("$origdir/manifest.override.json")
-    [ "$beta" -a "$sourcedir/manifest.beta.override.json" ] && \
+    [ "$beta" -a -f "$sourcedir/manifest.beta.override.json" ] && \
 	override+=("$sourcedir/manifest.beta.override.json")
-    [ "$origdir" -a "$beta" -a "$origdir/manifest.beta.override.json" ] && \
+    [ "$origdir" -a "$beta" -a -f "$origdir/manifest.beta.override.json" ] && \
 	override+=("$origdir/manifest.beta.override.json")
 
     python3 "$BASEDIR/scripts/makemanifest.py" \