Webserver: add dev build variant

This is to avoid falling back to debug when building with compile.sh.
It would build all the java, then when build all modules the webserver
will not have a dev variante, causing vlc-android to fallback to the
debug variant.

application/webserver/build.gradle

@@ -27,6 +27,10 @@ android {
             minifyEnabled false
             proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
         }
+        dev {
+            initWith debug
+            matchingFallbacks = ['debug']
+        }
     }
 
     task webCopy(type: Copy) {