Fix lateinit null value in resource detection; update Kotlin and gradle

app/src/main/java/at/bitfire/davdroid/ui/setup/DavResourceFinder.kt

@@ -163,7 +163,7 @@ class DavResourceFinder(
         try {
             val davBase = DavResource(httpClient.okHttpClient, baseURL, log)
 
-            lateinit var response: DavResponse
+            var response: DavResponse? = null
             try {
                 when (service) {
                     Service.CARDDAV -> {
@@ -200,7 +200,7 @@ class DavResourceFinder(
                         }
                     }
             } finally {
-                response.close()
+                response?.close()
             }
 
             // If a principal has been detected successfully, ensure that it provides the required service.

build.gradle

@@ -9,7 +9,7 @@
 // Top-level build file where you can add configuration options common to all sub-projects/modules.
 buildscript {
     ext.dokka_version = '0.9.16'
-    ext.kotlin_version = '1.2.41'
+    ext.kotlin_version = '1.2.50'
 
     repositories {
         jcenter()

gradle/wrapper/gradle-wrapper.properties

@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-4.6-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.8-all.zip