Running fedora rawhide with nouveau here (commence h8).

I tested both 32 and 64 bit libraries with glxinfo (compiled from mesa-utils) and confirmed that there aren't any issues with them, both are running with direct rendering.

Steam, however, is unable to find the correct libraries:

Running Steam on fedora 22 64-bit
STEAM_RUNTIME is enabled automatically
Installing breakpad exception handler for appid(steam)/version(1413917607)
libGL error: unable to load driver: nouveau_dri.so
libGL error: driver pointer missing
libGL error: failed to load driver: nouveau
libGL error: unable to load driver: swrast_dri.so
libGL error: failed to load driver: swrast
Installing breakpad exception handler for appid(steam)/version(1413917607)
Installing breakpad exception handler for appid(steamwebhelper)/version(20141020140456)
Installing breakpad exception handler for appid(steamwebhelper)/version(1413813896)
Installing breakpad exception handler for appid(steamwebhelper)/version(20141020140456)
Installing breakpad exception handler for appid(steamwebhelper)/version(1413813896)
Fontconfig error: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 70: non-double matrix element
Fontconfig error: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 70: non-double matrix element
Fontconfig warning: "/etc/fonts/conf.d/10-scale-bitmap-fonts.conf", line 78: saw unknown, expected number
[1106/155543:ERROR:nss_util.cc(1018)] Failed to load NSS libraries.
Fontconfig warning: "/etc/fonts/conf.d/65-0-lohit-bengali.conf", line 32: unknown element "langset"
libGL error: unable to load driver: nouveau_dri.so
libGL error: driver pointer missing
libGL error: failed to load driver: nouveau
libGL error: unable to load driver: swrast_dri.so
libGL error: failed to load driver: swrast
Error: OpenGL GLX context is not using direct rendering, which may cause performance problems.

For more information visit https://support.steampowered.com/kb_article.php?ref=9938-EYZB-7457.
Installing breakpad exception handler for appid(steam)/version(1413917607)
Installing breakpad exception handler for appid(steam)/version(1413917607)
Installing breakpad exception handler for appid(steam)/version(1413917607)
Installing breakpad exception handler for appid(steam)/version(1413917607)
Installing breakpad exception handler for appid(steam)/version(1413917607)
Generating new string page texture 7: 128x256, total string texture memory is 131.07 KB
Generating new string page texture 8: 64x256, total string texture memory is 196.61 KB
Generating new string page texture 9: 48x256, total string texture memory is 245.76 KB
Generating new string page texture 10: 256x256, total string texture memory is 507.90 KB

64bit glxinfo: http://pastebin.com/2036g19g
32bit glxinfo: http://pastebin.com/furwCFjs