Revert "extract_files: Add support for paths without system/"

This reverts commit 8b87b09ef7.
This will be addressed cleaner in the cleanup commit to follow.

Change-Id: Iec013bfafdbb334ab2657b10c433158002809b62

build/tools/extract_utils.sh

@@ -961,8 +961,6 @@ function extract() {
             TARGET="$FROM"
             OUTPUT_DIR="$OUTPUT_DIR/rootfs"
             TMP_DIR="$TMP_DIR/rootfs"
-        elif [ -f "$SRC/$FILE" ] && [ "$SRC" != "adb" ]; then
-            TARGET="$FROM"
         else
             TARGET="system/$FROM"
             FILE="system/$FILE"