Get rid of embedded NUL characters in the string.
Get rid of embedded NUL characters in the string.

This fixes questionmarks appearing in the plain text version
of a multipart/alternative mail which had a multiline HTML
signature.

svn path=/trunk/KDE/kdepim/; revision=812469

lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi,lefou/kdepim-noakonadi