Fedora 21 has renamed the X server to Xorg.bin. This is how the process line looks:
$ ps -eo comm,command|grep Xorg
Xorg.bin /usr/libexec/Xorg.bin :0 -background none -noreset -verbose 3 -logfile /dev/null -auth /run/gdm/auth-for-gdm-Zt8Eq2/database -seat seat0 -nolisten tcp vt1
Created attachment 239733 [details]
Comment on attachment 239733 [details]
Clearing flags on attachment: 239733
Committed r174656: <http://trac.webkit.org/changeset/174656>
All reviewed patches have been landed. Closing bug.