INT-3657: Default MaxMessPerPoll=1 for @InboundCA

JIRA: https://jira.spring.io/browse/INT-3657

With XML/DSL, the MMPP defaults to 1 (via the SPCAFB) but
@InboundChannelAdapter defaulted to -1 (infinity).

Change the annotation to be consistent with the XML/DSL.

Add missing schema docs for the `basePollerType`.

* Fix `AbstractMethodAnnotationPostProcessor` for `maxMessagesPerPollValue` override
* Change `EnableIntegrationTests#foo()` `@InboundChannelAdapter` to use `maxMessagesPerPoll = "2"`
and modify appropriate test-case to be sure that `maxMessagesPerPoll` isn't overriden as it has been done in the original commit.

spring-integration-jdbc/src/test/java/org/springframework/integration/jdbc/StoredProcJavaConfigTests.java

@@ -74,6 +74,7 @@ public class StoredProcJavaConfigTests {
 		Collection<?> primes = (Collection<?>) received.getPayload();
 		assertThat(primes, Matchers.<Object>contains(2, 3, 5, 7));
 		received = fooChannel.receive(100);
+		// verify maxMessagesPerPoll == 1
 		assertNull(received);
 	}
 
@@ -87,7 +88,7 @@ public class StoredProcJavaConfigTests {
 		}
 
 		@Bean
-		@InboundChannelAdapter(value = "fooChannel", poller = @Poller(fixedDelay="5000", maxMessagesPerPoll = "1"))
+		@InboundChannelAdapter(value = "fooChannel", poller = @Poller(fixedDelay="5000"))
 		public MessageSource<?> storedProc() {
 			StoredProcPollingChannelAdapter source = new StoredProcPollingChannelAdapter(storedProcExecutor());
 			source.setExpectSingleResult(true);