It's a closet. Not much point in a CFL in a closet, is there? Seems the perfect place to save $2 and just use a cheap ole ordinary bulb.
Ya have to keep in your mind there are some motion switch are NOT designed to work with screwin CFL lamp because some of the motion switch need a " close circuit" to keep thier electronic going and with electronic CFL it will keep them in open or failure mode unless you put in indescent lamp in there.
If this were the case, it would work if you put in a double-bulb fixture with a an incandescent and a CFL. I've tried this on a motion-sensor switch in my house, but the CFLs flicker and die in just in a few weeks of intermittant use. I've seen the same problem with dimmers and electric eyes.
One odd thing... We put up a 13-bulb chandalier on a standard lutron dimmer (the kind explicitely not rated for CFL), and on a whim, I replaced one of the 40W incandescents with a 15W ("60W") CFL. And the damned thing works great- puts out more light than the incandescents and actually dims better, too. And, inexplicably, has NOT suffered an early death. This is a cheap CFL too, out of a $10 wal-mart 6-pack. I'm at a loss to explain why this works where others don't.