Between the Ashes HPC request: extend ai-chase-same-team to ai-disarm, ai-disable, and ai-destroy-subsys too

git-svn-id: svn://svn.icculus.org/fs2open@11097 387891d4-d844-0410-90c0-e4c51a9137d3
stupid missing parenthesis >.>

git-svn-id: svn://svn.icculus.org/fs2open@11098 387891d4-d844-0410-90c0-e4c51a9137d3
related to Mantis #2971: properly reset shield info when we have a null objp

git-svn-id: svn://svn.icculus.org/fs2open@11099 387891d4-d844-0410-90c0-e4c51a9137d3