Changed each to all, since each is out of date. And added more generic replacement.

build.gradle

android {
    defaultConfig {
        versionName "actionbar"
    }
    signingConfigs {
        release {
            storeFile file("android.keystore")
            ...
        }
    }
    sourceSets {
        main {
            manifest.srcFile 'AndroidManifest.xml'
            res.srcDirs = ['res']
            assets.srcDirs = ['assets']
        }
    }

    buildTypes {
        debug {
            versionNameSuffix "dev"
        }
        release {
            signingConfig signingConfigs.release
        }
    }

    buildToolsVersion "17.0"
    compileSdkVersion 17
}

project.archivesBaseName = "Acme-Project-REPLACEME";

android.applicationVariants.all { variant ->
        def apk = variant.outputFile

        def newManifest = variant.processManifest.manifestOutputFile
        def versionCode = getVersionCode(newManifest.path)
        if (versionCode == -1) {
            return
        }
        
        def newName
    
        if (variant.buildType.name == "release") {
            newName = apk.name.replace("REPLACEME", versionCode);
        } else {
            newName = apk.name.replace("REPLACEME", "");
        }

        //noinspection GroovyAssignabilityCheck
        variant.outputFile = new File(apk.parentFile, newName)
}