Two years ago he reopened his gallery in SoHo. And now, he’s taken his first step toward a Los Angeles comeback: He has just signed a lease for a 15,000-square-foot warehouse in Hollywood with plans to open a gallery there in the fall. The art dealer’s new space, at 925 North Orange Drive, is a few blocks from the strip of galleries lining Highland Avenue, anchored by Regen Projects and Kohn Gallery.