Fix bugs in the retraction code

Fix bugs in the retraction code

Currently, the following seems to be the functional status:
	For a Diaspora top-level post:
		Friendica comments show up AND delete
		Diaspora comments show up AND delete for top-level owner
		Diaspora comments show up for non-owner
		Diaspora comments sometimes don't delete for non-owner
			-> Appears to be Diaspora's fault, as a "not a valid object" error shows up in the log

		Friendica likes show up, but can't unlike (Friendica doesn't even message Diaspora)
		Diaspora likes show up
		Diaspora non-owner can't unlike
			-> Same as comments, seems to be Diaspora's fault

	For a Friendica top-level post:
		Friendica comments show up AND delete
		Diaspora comments show up AND delete

		Friendica likes don't show up in Diaspora sometimes
		Friendica doesn't even message Diaspora for unlikes (sometimes?)
		Diaspora likes and unlikes work