Fix launchctl not being able to stop bitcoind

bitcoind should not be launched as daemon from launchctl. Otherwise, the
process cannot be stopped from launchctl.

contrib/init/org.bitcoin.bitcoind.plist

@@ -7,7 +7,6 @@
 	<key>ProgramArguments</key>
 	<array>
 		<string>/usr/local/bin/bitcoind</string>
-		<string>-daemon</string>
 	</array>
 	<key>RunAtLoad</key>
 	<true/>