i18n: Correct storage pool create error message

The message displayed when an invalid Storage Pool name is entered is
not a valid English sentence.  Change:

-"The Storage Pool Name should be at least one of word characters, "
-"underscores, or hyphens."

 - to -

+"Invalid Storage Pool name.  It may only contain letters, numbers, "
+"underscores, and hyphens."

I have blanked out the zh_CN translation in case it needs to be updated.

Signed-off-by: Adam Litke <agl@linux.vnet.ibm.com>
Issue #125: Switching Page Tabs Breaks Pop-up Menu Disappearing

V2 -> V3:
  3a) Rebase.
  3b) Add commit message.

v1 -> V2:
  2a) Rebase.

Pop-up menu depends on document's mouse click event to disappear.
In former implementation, click event listener was bound and will
be triggered. The problem is that "return false" will prevent the
click event to bubble to document node. In this patch, we'll take
"event.preventDefault()" to avoid <a href> redirecting browser to
other pages and still bubble click event to document.

    Tested on IE9, IE10, Firefox 22, Chrome, and Safari.

Signed-off-by: Hongliang Wang <hlwang@linux.vnet.ibm.com>
Reviewed-by: Meina Zhou <zhoumein@linux.vnet.ibm.com>