Redefine coverity version of the BUG macro

Our BUG macro definition is all wrong for coverity.

We shouldn't be including coverity_panic, since hitting a BUG doesn't actually mean Tor will crashed, and we shouldn't imply that the condition might be visited anyway. We should just do "#define BUG(x) (x)" when we're building with coverity.

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information