Programmatically set context id rather than using spring.application.name.

This allows other bootstrap application listeners to resolve the
spring.application.name during the bootstrap phase, but allows bootstrap
to determine if the context is the bootstrap context.

fixes gh-214

spring-cloud-context/src/main/java/org/springframework/cloud/bootstrap/BootstrapApplicationListener.java

@@ -138,7 +138,6 @@ public class BootstrapApplicationListener
 				.resolvePlaceholders("${spring.cloud.bootstrap.location:}");
 		Map<String, Object> bootstrapMap = new HashMap<>();
 		bootstrapMap.put("spring.config.name", configName);
-		bootstrapMap.put("spring.application.name", configName);
 		if (StringUtils.hasText(configLocation)) {
 			bootstrapMap.put("spring.config.location", configLocation);
 		}
@@ -176,6 +175,10 @@ public class BootstrapApplicationListener
 		AnnotationAwareOrderComparator.sort(sources);
 		builder.sources(sources.toArray(new Class[sources.size()]));
 		final ConfigurableApplicationContext context = builder.run();
+		// gh-214 using spring.application.name=bootstrap to set the context id via
+		// `ContextIdApplicationContextInitializer` prevents apps from getting the actual spring.application.name
+		// during the bootstrap phase.
+		context.setId("bootstrap");
 		// Make the bootstrap context a parent of the app context
 		addAncestorInitializer(application, context);
 		// It only has properties in it now that we don't want in the parent so remove
@@ -192,12 +195,6 @@ public class BootstrapApplicationListener
 			return;
 		}
 		PropertySource<?> source = bootstrap.get(name);
-		if (source instanceof MapPropertySource) {
-			Map<String, Object> map = ((MapPropertySource) source).getSource();
-			// The application name is "bootstrap" (by default) at this point and
-			// we don't want that to appear in the parent context at all.
-			map.remove("spring.application.name");
-		}
 		if (!environment.contains(name)) {
 			environment.addLast(source);
 		}