gspawn: Abort if we can't open /dev/null
gspawn: Abort if we can't open /dev/null

This really "shouldn't happen", but if we have an assertion here, it
will help static analysis tools know we're not hitting undefined
state.

darren-clark/android_platform_external_bluetooth_glib,bluez-android/glib,pstglia/external-bluetooth-glib,iConsole/Console-OS_external_bluetooth_glib,bluez-android/glib,iConsole/Console-OS_external_bluetooth_glib,justinkb/aosp-bluez.glib,pstglia/external-bluetooth-glib,iConsole/Console-OS_external_bluetooth_glib,pstglia/platform-external-bluetooth-glib,01org/android-bluez-glib,iConsole/Console-OS_external_bluetooth_glib,bluez-android/glib,pstglia/external-bluetooth-glib,justinkb/aosp-bluez.glib,pstglia/external-bluetooth-glib,01org/android-bluez-glib,01org/android-bluez-glib,pstglia/platform-external-bluetooth-glib,darren-clark/android_platform_external_bluetooth_glib,bluez-android/glib,pstglia/platform-external-bluetooth-glib,justinkb/aosp-bluez.glib,01org/android-bluez-glib,pstglia/external-bluetooth-glib,darren-clark/android_platform_external_bluetooth_glib,justinkb/aosp-bluez.glib,01org/android-bluez-glib,pstglia/platform-external-bluetooth-glib,iConsole/Console-OS_external_bluetooth_glib,bluez-android/glib,pstglia/platform-external-bluetooth-glib,darren-clark/android_platform_external_bluetooth_glib,justinkb/aosp-bluez.glib,darren-clark/android_platform_external_bluetooth_glib