Don't log DEBUG data out of c3p0's SqlUtils class

Signed-off-by: Shawn O. Pearce <sop@google.com>
diff --git a/src/main/java/log4j.properties b/src/main/java/log4j.properties
index 051f623..e34116b 100644
--- a/src/main/java/log4j.properties
+++ b/src/main/java/log4j.properties
@@ -13,3 +13,4 @@
 #
 log4j.logger.com.mchange.v2.c3p0=WARN
 log4j.logger.com.mchange.v2.resourcepool=WARN
+log4j.logger.com.mchange.v2.sql=WARN