(petitioner provided security services to businesses during his time when he was an off-duty police officer; petitioner reported his service income on "other income" line on return; petitioner determined to be independent contractor and income subject to self-employment tax; petitioner also failed to qualify as real estate professional under I.R.C. Sec. 469(c)(7)(B) for failure to meet the 750-hour test and failure to meet the more than 50 percent test).