Bug 593823: put tabs on top by default for Linux, r=gavin, a=beltzner for b7

browser/base/content/browser.xul

@@ -826,12 +826,7 @@
 #ifdef WINCE
            defaulticonsize="small" iconsize="small"
 #endif
-#ifdef XP_WIN
            tabsontop="true"
-#endif
-#ifdef XP_MACOSX
-           tabsontop="true"
-#endif
            persist="tabsontop">
     <!-- Menu -->
     <toolbar type="menubar" id="toolbar-menubar" class="chromeclass-menubar" customizable="true"