Don't show paths in wp_upload_dir()

[nacin]

wp_upload_dir() unnecessarily shows the full path to an upload directory in case it can't create it. We shouldn't even bother showing the path at all — an error of "Error uploading file. Is the uploads directory writeable by the server?" should be sufficient.

[nacin]

In [21757]:

A more generic message for wp_upload_dir(). see #21796, for 3.4.

[nacin]

For 3.5, I'm debating between [21757] and a generic "Error uploading file. Is the uploads directory writeable by the server?" [21757] was designed to not break the string.

[SergeyBiryukov]

I'd prefer [21757]. With a generic message, new users would have to guess where the uploads directory is.

[ryan]

In [22276]:

A more generic message for wp_upload_dir(). Props nacin. fixes #21796