[#3436] fixed compilation

Author: Razvan Becheriu

src/lib/pgsql/pgsql_exchange.h

@@ -386,7 +386,7 @@ struct PsqlBindArray {
         if (value.unspecified()) {
             addNull();
         } else {
-            add(value);
+            add(value.get());
         }
     }
 

src/lib/pgsql/tests/pgsql_exchange_unittest.cc

@@ -216,8 +216,8 @@ TEST(PsqlBindArray, addOptionalBool) {
     // Verify contents are correct.
     std::string expected =
         "0 : empty\n"
-        "1 : \"0\"\n"
-        "2 : \"1\"\n";
+        "1 : \"FALSE\"\n"
+        "2 : \"TRUE\"\n";
 
     EXPECT_EQ(expected, b.toText());
 }