[FIX] py.js: bug in tokenization of single-quoted empty string

bzr revid: xmo@openerp.com-20121129132738-fcnam8bkqyt7h8ey

addons/web/static/lib/py.js/.hg_archival.txt

@@ -1,5 +1,5 @@
 repo: 076b192d0d8ab2b92d1dbcfa3da055382f30eaea
-node: ccf62e5d0291f66a39f4049f3e880004e59c3654
+node: 2b62048dd1d86c45e4bf0442b5da4122534132bf
 branch: default
 latesttag: 0.7
-latesttagdistance: 4
+latesttagdistance: 5

addons/web/static/lib/py.js/lib/py.js

@@ -311,7 +311,7 @@ var py = {};
                 } else if (string_pattern.test(token)) {
                     var m = string_pattern.exec(token);
                     tokens.push(create(symbols['(string)'], {
-                        value: m[2] || m[3]
+                        value: (m[2] !== undefined ? m[2] : m[3])
                     }));
                 } else if (token in symbols) {
                     var symbol;