Made log message less terrifying.

I don't like to see the words "Aborting creation." when I'm in the middle of
creating databases. If we're not creating the index, fine, but don't give me
the idea that we're aborting the entire creation of the table.

src/main/java/com/samskivert/depot/impl/BuildVisitor.java

@@ -490,7 +490,7 @@ public abstract class BuildVisitor implements FragmentVisitor<Void>
         if (!_allowComplexIndices) {
             for (Tuple<SQLExpression<?>, Order> field : createIndexClause.getFields()) {
                 if (!(field.left instanceof ColumnExp<?>)) {
-                    log.warning("This database can't handle complex indexes. Aborting creation.",
+                    log.warning("This database can't handle complex indexes. Not creating.",
                         "ixName", createIndexClause.getName());
                     return null;
                 }