Fix for Mantis 1863 (Ships with an arrival cue of true and a delay do not arrive on the standalone). Might possibly fix Mantis 1815 too. 

git-svn-id: svn://svn.icculus.org/fs2open/trunk/fs2_open@9683 387891d4-d844-0410-90c0-e4c51a9137d3
Assign the debris signature correctly.

git-svn-id: svn://svn.icculus.org/fs2open/trunk/fs2_open@9684 387891d4-d844-0410-90c0-e4c51a9137d3
Better error reporting for this issue (in order to help track down a Diaspora bug).

git-svn-id: svn://svn.icculus.org/fs2open/trunk/fs2_open@9685 387891d4-d844-0410-90c0-e4c51a9137d3
We only need to see this error once in FS2. Ensure that this instance only appears in FRED. 

git-svn-id: svn://svn.icculus.org/fs2open/trunk/fs2_open@9686 387891d4-d844-0410-90c0-e4c51a9137d3