Don't calculate exclusions for non transitive configurations

All direct dependencies of a configuration are included by default and
all other are excluded by default for non transitive configurations. It
is therefore unnecessary to calculate exclusions.

See gh-372

Author: fp7

src/main/java/io/spring/gradle/dependencymanagement/internal/ExclusionConfiguringAction.java

@@ -96,6 +96,9 @@ private void applyMavenExclusions(ResolvableDependencies resolvableDependencies)
 	}
 
 	private Set<DependencyCandidate> findExcludedDependencies() {
+		if (!this.configuration.isTransitive()) {
+			return Collections.emptySet();
+		}
 		ResolutionResult resolutionResult = copyConfiguration().getIncoming().getResolutionResult();
 		ResolvedComponentResult root = resolutionResult.getRoot();
 		Set<DependencyCandidate> excludedDependencies = new HashSet<>();