Fix invalid 'in' operand in values()

[Ken-Patrick]

invalid 'in' operand obj base.jsm:446 values resource://dactyl/base.jsm:446:1 BookmarkCache<["@@iterator"] resource://dactyl/bookmarkcache.jsm:97:16 BookmarkCache<.keywords< resource://dactyl/bookmarkcache.jsm:104:1 g_Memoize resource://dactyl/base.jsm:1051:64 search resource://dactyl-content/bookmarks.js:700:17 completer resource://dactyl-content/bookmarks.js:665:21 forkapply resource://dactyl/completion.jsm:820:23 fork resource://dactyl/completion.jsm:807:16 completions resource://dactyl/options.jsm:819:20 validateCompleter resource://dactyl/options.jsm:834:26 validator resource://dactyl/options.jsm:418:20 isValidValue resource://dactyl/options.jsm:241:16 op resource://dactyl/options.jsm:272:18 setAction resource://dactyl/options.jsm:1324:35 initCommands/</< resource://dactyl/options.jsm:1517:21 exec resource://dactyl/commands.jsm:193:17 trapErrors resource://dactyl-content/dactyl.js:1159:20 execute resource://dactyl/commands.jsm:182:17 execute resource://dactyl-content/dactyl.js:555:26 execute/</< resource://dactyl/commands.jsm:812:33 withSavedValues resource://dactyl/base.jsm:1103:20 execute/< resource://dactyl/commands.jsm:779:21 withContext/< resource://dactyl/contexts.jsm:612:20 withSavedValues resource://dactyl/base.jsm:1103:20 withContext resource://dactyl/contexts.jsm:610:16 execute resource://dactyl/commands.jsm:777:17 Local/source/< resource://dactyl/io.jsm:191:29 withContext/< resource://dactyl/contexts.jsm:612:20 withSavedValues resource://dactyl/base.jsm:1103:20 withContext resource://dactyl/contexts.jsm:610:16 source resource://dactyl/io.jsm:137:24 initLoad/< resource://dactyl-content/dactyl.js:2025:29 timeout/timeout_notify resource://dactyl/base.jsm:1134:17