Time zone guessing improved, fixes 'Assuming time zone Etc/GMT for Etc/GMT-2'

app/src/main/java/at/bitfire/davdroid/resource/Event.java

@@ -349,14 +349,27 @@ public class Event extends Resource {
             return;
 
         String localTZ = Time.TIMEZONE_UTC;
-		
+        boolean foundMatch = false;
         String availableTZs[] = SimpleTimeZone.getAvailableIDs();
-		for (String availableTZ : availableTZs)
-			if (tzID.indexOf(availableTZ, 0) != -1) {
+
+        // Try to find an exact match
+        for (String availableTZ : availableTZs) {
+            if (tzID.equals(availableTZ)) {
                 localTZ = availableTZ;
+                foundMatch = true;
                 break;
             }
+        }
 
+        if (!foundMatch) {
+            // Try to find something else that matches
+            for (String availableTZ : availableTZs) {
+                if (tzID.indexOf(availableTZ, 0) != -1) {
+                    localTZ = availableTZ;
+                    break;
+                }
+            }
+        }
         Log.d(TAG, "Assuming time zone " + localTZ + " for " + tzID);
         date.setTimeZone(tzRegistry.getTimeZone(localTZ));
     }