I STILL DO (45 RPM LP)Reuniting with producer Glyn Johns, the steady hand who guided Slowhand back in 1977, doesn't provide Eric Clapton with much of a jolt for his 23rd studio album, but it does provide the veteran guitarist with no small degree of nicely weathered warmth. Such mellowed good vibes are the calling card of I Still Do, which otherwise proceeds along the same path Clapton's records follow in the 21st century: he blends covers of well worn blues standards with