Make AaptGroupEntry::getMncName accept mnc00

MNC 00 is a valid network code and is used by
some operators, see http://en.wikipedia.org/wiki/Mobile_Network_Code.

Remove the test that checks if atoi returns zero.
The string is validated to contain only numbers
already.

Also discussed here:
https://code.google.com/p/android/issues/detail?id=3657

Change-Id: I3220d7980abe4067c9e7aa4cbc10b5fd0b8c9ea7
diff --git a/tools/aapt/AaptAssets.cpp b/tools/aapt/AaptAssets.cpp
index e4f447e..2b2ec7b 100644
--- a/tools/aapt/AaptAssets.cpp
+++ b/tools/aapt/AaptAssets.cpp
@@ -685,13 +685,11 @@
     if (*c != 0) return false;
     if (c-val == 0 || c-val > 3) return false;
 
-    int d = atoi(val);
-    if (d != 0) {
-        if (out) out->mnc = d;
-        return true;
+    if (out) {
+        out->mnc = atoi(val);
     }
 
-    return false;
+    return true;
 }
 
 /*