ci: use Diawi URL for iOS only if it's set

Signed-off-by: Jakub Sokołowski <jakub@status.im>

ci/ghcmgr.groovy

@@ -11,7 +11,7 @@ utils = load 'ci/utils.groovy'
 def buildObj(success) {
   def pkg_url = env.PKG_URL
   /* a bare ipa file is not installable on iOS */
-  if (env.TARGET == 'ios') {
+  if (env.TARGET == 'ios' && env.DIAWI_URL != "") {
     pkg_url = env.DIAWI_URL 
   }
   /* assemble build object valid for ghcmgr */

ci/ios.groovy

@@ -63,6 +63,7 @@ def uploadToDiawi() {
   withCredentials([
     string(credentialsId: 'diawi-token', variable: 'DIAWI_TOKEN'),
   ]) {
+    /* This can silently fail with 'File is not processed.' */
     nix.shell(
       'bundle exec --gemfile=fastlane/Gemfile fastlane ios upload_diawi',
       keep: ['FASTLANE_DISABLE_COLORS', 'DIAWI_TOKEN'],