Prevent space before ellipsis when truncating

When truncating a string at a point where it contains a space (ie "hello
world" to 9 chars), the resultant string will have a space before the
ellipsis ("hello ..."). This is both gramatically incorrect and just looks
wrong, and is fixed by trimming the string before appending the ellipsis.

Change-Id: Iec86b17bfc8c50e4c1a96fd373861841fc57848d
Merge "Prevent space before ellipsis when truncating"