Polish caught exception names

Prefer `ex` over `e`.

spring-boot-actuator/src/main/java/org/springframework/boot/actuate/cloudfoundry/CloudFoundrySecurityService.java

@@ -109,7 +109,7 @@ class CloudFoundrySecurityService {
 			return extractTokenKeys(this.restTemplate
 					.getForObject(getUaaUrl() + "/token_keys", Map.class));
 		}
-		catch (HttpStatusCodeException e) {
+		catch (HttpStatusCodeException ex) {
 			throw new CloudFoundryAuthorizationException(Reason.SERVICE_UNAVAILABLE,
 					"UAA not reachable");
 		}

spring-boot-actuator/src/test/java/org/springframework/boot/actuate/metrics/statsd/StatsdMetricWriterTests.java

@@ -151,7 +151,7 @@ public class StatsdMetricWriterTests {
 				try {
 					Thread.sleep(50L);
 				}
-				catch (InterruptedException e) {
+				catch (InterruptedException ex) {
 					Thread.currentThread().interrupt();
 				}
 			}