Restore commons-logging dependency for spring-boot

Restore the dependency on commons-logging (transitively via spring-core)
for spring-boot. This means that we are not tied directly to SLF4J, but
it is still an option that can be used via `jcl-over-slf4j`.

The `spring-boot-starter-parent` continues to replace `commons-logging`
with `jcl-over-slf4j`.

Fixes gh-981

spring-boot/pom.xml

@@ -20,10 +20,6 @@
 	</properties>
 	<dependencies>
 		<!-- Compile -->
-		<dependency>
-			<groupId>org.slf4j</groupId>
-			<artifactId>jcl-over-slf4j</artifactId>
-		</dependency>
 		<dependency>
 			<groupId>org.springframework</groupId>
 			<artifactId>spring-core</artifactId>
@@ -154,6 +150,11 @@
 			<artifactId>spring-webmvc</artifactId>
 			<scope>test</scope>
 		</dependency>
+		<dependency>
+			<groupId>org.slf4j</groupId>
+			<artifactId>jcl-over-slf4j</artifactId>
+			<scope>test</scope>
+		</dependency>
 	</dependencies>
 	<build>
 		<plugins>