systemd: DISTRO_FEATURES_INITMAN is gone in master

The DISTRO_FEATURES_INITMAN variable has been removed, use
VIRTUAL-RUNTIME_init_manager which is still present. We have
already defined the later in our poky builds

conf/machine/include/sysmobts.inc

@@ -20,7 +20,7 @@ MACHINE_FEATURES = "kernel26 serial"
 
 MACHINE_ESSENTIAL_EXTRA_RDEPENDS = "\
 	busybox-ifplugd \
-	${@['watchdog', ''][d.getVar('DISTRO_FEATURES_INITMAN', True) == 'systemd']} \
+	${@['watchdog', ''][d.getVar('VIRTUAL-RUNTIME_init_manager', True) == 'systemd']} \
 	kernel \
 	kernel-module-davinci-wdt \
 	kernel-module-dspdl \
@@ -38,7 +38,7 @@ IMAGE_FSTYPES ?= "tar.bz2 cpio.gz ubifs ubi jffs2"
 MACHINE_EXTRA_RDEPENDS = "\
 	task-sysmocom-bts \
 	sysmobts-firmware \
-	${@['watchdog', ''][d.getVar('DISTRO_FEATURES_INITMAN', True) == 'systemd']} \
+	${@['watchdog', ''][d.getVar('VIRTUAL-RUNTIME_init_manager', True) == 'systemd']} \
 	"
 #MACHINE_EXTRA_RRECOMMENDS = "dsplink-module"