Make spring-cloud-dataflow-server jar executable (spring-attic#4956)

Fixes spring-attic#4941

Author: onobc

spring-cloud-dataflow-server/pom.xml

@@ -135,6 +135,9 @@
 			<plugin>
 				<groupId>org.springframework.boot</groupId>
 				<artifactId>spring-boot-maven-plugin</artifactId>
+				<configuration>
+					<executable>true</executable>
+				</configuration>
 			</plugin>
 			<plugin>
 				<artifactId>maven-javadoc-plugin</artifactId>