Sacramento musicians and their followers are waiting to see whether this summer brings an end to an era of live music at Old Ironsides. Countless local bands broke into the music business at the bar/restaurant known as "Old I" over the last two decades. But there's currently only one weekend show booked for July. Two shows that had been set for next month have been moved to another location, one has been canceled and future bookings have been postponed for now. The family that has owned the bar at 1901 10th St. for 76 years is working to replace a rented sound system that was removed Sunday. The Kanelos family rented the system for about 17 years and was unable to negotiate a lower fee