Pg: Don't return self on / cache() or text_*() methods

This is much too easy of a footgun:

  $db->cache->q(...);

Enabled cache on the $db object, not just for the given query.

FU.xs

@@ -55,7 +55,6 @@
         if (!ix) ix = FUPG_CACHE;\
         if (items == 1 || SvTRUE(ST(1))) x->stflags |= ix; \
         else x->stflags &= ~ix; \
-        XSRETURN(1); \
     } while(0)
 
 MODULE = FU
@@ -343,6 +342,7 @@ void cache(fupg_st *x, ...)
   CODE:
     if (ix == 0 && x->prepared) fu_confess("Invalid attempt to change statement configuration after it has already been prepared or executed");
     FUPG_STFLAGS;
+    XSRETURN(1);
 
 void exec(fupg_st *st)
   CODE: