pacman-key: remove holdkeys functionality

We're putting the cart ahead of the horse a bit here. Given that our
keyring is not one where everything is implicitly trusted (ala gpgv),
keeping or deleting a key has no bearing on its trusted status, only
whether we can actually verify things signed by said key.

If we need to address this down the road, we can find a solution that
works for the problem at hand rather than trying to solve it now before
signing is even widespread.

Signed-off-by: Dan McGee <dan@archlinux.org>

doc/pacman-key.8.txt

@@ -121,9 +121,7 @@ manually import to the pacman keyring. This prevents a potentially malicious
 repository adding keys to the pacman keyring without the users knowledge.
 
 A key being marked as revoked always takes priority over the key being added to
-the pacman keyring, regardless of the keyring it is provided in. To prevent a
-key from being revoked when using '\--populate', its ID can be listed in
-+{sysconfdir}/pacman.d/gnupg/holdkeys+.
+the pacman keyring, regardless of the keyring it is provided in.
 
 See Also
 --------

scripts/pacman-key.sh.in

@@ -288,18 +288,6 @@ populate_keyring() {
 		fi
 	done
 
-	# Read list of keys that must be kept installed and remove them from the list
-	# of keys to be removed
-	if [[ -f "${PACMAN_KEYRING_DIR}/holdkeys" ]]; then
-		while read key; do
-			key_id="$("${GPG_PACMAN[@]}" --quiet --with-colons --list-key "${key}" 2>/dev/null | grep ^pub | cut -d: -f5)"
-			if [[ -n "${revoked_ids[$key_id]}" ]]; then
-				unset revoked_ids[$key_id]
-			fi
-		done < "${PACMAN_KEYRING_DIR}/holdkeys"
-	fi
-
-	# Remove the keys not marked to keep
 	if (( ${#revoked_ids[@]} > 0 )); then
 		msg "$(gettext "Disabling revoked keys in keyring...")"
 		for key_id in "${!revoked_ids[@]}"; do