CORDA-1915 Simm Valuation demo update for JAR signing (#4105)

The build process creates new version fo Cordapp JAR in post 'jar' task.
So far JAR signing was integral part of the jar task, now it's also available as a separate task signJar (gradle-plugins PR corda/corda-gradle-plugins#130).
Using signJar to re-sign Cordapp shrinked JAR.

samples/simm-valuation-demo/build.gradle

@@ -71,9 +71,6 @@ task deployNodes(type: net.corda.plugins.Cordform, dependsOn: ['jar', nodeTask,
         cordapp project(':samples:simm-valuation-demo:flows')
         rpcUsers = [['username': "default", 'password': "default", 'permissions': [ 'ALL' ]]]
     }
-    signing {
-        enabled false
-    }
     node {
         name "O=Notary Service,L=Zurich,C=CH"
         notary = [validating : true]

samples/simm-valuation-demo/contracts-states/build.gradle

@@ -9,8 +9,7 @@ cordapp {
         targetPlatformVersion = corda_platform_version.toInteger()
     }
     signing {
-        // We need to sign the output of the "shrink" task,
-        // but the jar signer doesn't support that yet.
+        // Cordapp is signed after the "shrink" task.
         enabled false
     }
     sealing {
@@ -79,8 +78,14 @@ task shrink(type: ProGuardTask) {
     keepclassmembers 'class com.google.** { *; }', includedescriptorclasses:true
     keepclassmembers 'class org.joda.** { *; }', includedescriptorclasses:true
 }
+
+task sign(type: net.corda.plugins.SignJar) {
+    inputJars shrink
+}
+
 jar.finalizedBy shrink
+shrink.finalizedBy sign
 
 artifacts {
-    shrinkArtifacts file: shrinkJar, name: project.name, type: 'jar', extension: 'jar', classifier: 'tiny', builtBy: shrink
+    shrinkArtifacts file: sign.outputJars.singleFile, name: project.name, type: 'jar', extension: 'jar', classifier: 'tiny', builtBy: sign
 }

samples/simm-valuation-demo/flows/build.gradle

@@ -6,9 +6,6 @@ cordapp {
         vendor = 'R3'
         targetPlatformVersion = corda_platform_version.toInteger()
     }
-    signing {
-        enabled false
-    }
     sealing {
         // Cannot seal JAR because other module also defines classes in the package net.corda.vega.analytics
         enabled false
@@ -38,3 +35,7 @@ dependencies {
     compile "com.opengamma.strata:strata-loader:$strata_version"
     compile "com.opengamma.strata:strata-math:$strata_version"
 }
+
+jar {
+    duplicatesStrategy = DuplicatesStrategy.EXCLUDE
+}