fallback to remove components one by one when failing to remove a bundle

[mockersf]

fixes #698
when failing to remove a bundle, issue a warn log and fallback to remove components from bundle one by one instead of panicking.

see #710 for discussion on fallback

[cart]

Retrieving the location here and in remove() is redundant work. I'd prefer it if we found a way to only do this once (ex: pass the location into remove_bundle_internal)

[mockersf]

That was not possible, as location needs to be an &mut that references self, which also needs to be an &mut to call remove_bundle_internal.

I was able to remove getting the location from remove by retrieving the bundle value in remove_bundle_internal. When coming from remove_one_by_one, this will not return the expected value as we actually can't get it, that's why there is a parameter check_presence set to false when coming from this function...

[cart]

rebased / updated to master (by using tracing instead of log). I also reverted the "only get location once in normal path" changes. Looking up locations is just an array lookup. I don't think its worth the added branching (and return complexity) to remove it.

We can always just duplicate code if we need to, but in this case its all probably in the noise anyway.

I also removed the uber unsafe block in favor of slightly more scoped blocks.