Add support for DATETIME() function call as a SQLite default values.

Fixes #1177.

src/sources/sqlite/sqlite-cast-rules.lisp

@@ -107,6 +107,12 @@
                           (string= "CURRENT TIMESTAMP" default)))
                  :current-timestamp)
 
+                ((and (stringp default)
+                      ;; we don't care about spaces in that expression
+                      (string-equal "datetime('now','localtime')"
+                                    (remove #\Space default)))
+                 :current-timestamp)
+
                 ((and (stringp default) (string-equal "current_date" default))
                  :current-date)