am 83ec0010: am a77bef47: Document the adb install -d option.

        "  adb forward --remove <local> - remove a specific forward socket connection\n"

        "  adb forward --remove-all     - remove all forward socket connections\n"

        "  adb jdwp                     - list PIDs of processes hosting a JDWP transport\n"

        "  adb install [-l] [-r] [-s] [--algo <algorithm name> --key <hex-encoded key> --iv <hex-encoded iv>] <file>\n"

        "  adb install [-l] [-r] [-d] [-s] [--algo <algorithm name> --key <hex-encoded key> --iv <hex-encoded iv>] <file>\n"

        "                               - push this package file to the device and install it\n"

        "                                 ('-l' means forward-lock the app)\n"

        "                                 ('-r' means reinstall the app, keeping its data)\n"

        "                                 ('-d' means allow version code downgrade)\n"

        "                                 ('-s' means install on SD card instead of internal storage)\n"

        "                                 ('--algo', '--key', and '--iv' mean the file is encrypted already)\n"

        "  adb uninstall [-k] <package> - remove this app package from the device\n"