Okay, here's what's in the error log after making that change and restarting:
[ 2017-08-15 17:31:25.5571 12825/b7369700 apa/Hooks.cpp:1261 ]: Initializing Phusion Passenger...
[ 2017-08-15 17:31:25.5760 12825/b7369700 WatchdogLauncher.h:376 ]: File descriptor opened: 13
[ 2017-08-15 17:31:25.5760 12825/b7369700 WatchdogLauncher.h:376 ]: File descriptor opened: 14
[ 2017-08-15 17:31:25.5767 12825/b7369700 FileDescriptor.h:94 ]: File descriptor closed: 14
[ 2017-08-15 17:31:25.5767 12825/b7369700 WatchdogLauncher.h:438 ]: File descriptor purpose: 13: WatchdogLauncher: feedback FD
[ 2017-08-15 17:31:25.6901 12825/b7369700 FileDescriptor.h:84 ]: File descriptor closed: 13
[Tue Aug 15 17:31:25.690254 2017] [passenger:error] [pid 12825:tid 3073808128] *** Passenger could not be initialized because of this error: Unable to start the Phusion Passenger watchdog: it seems to have been killed with signal SIGSEGV during startup