Bug 1278863 - fix delete/delete[] mismatch in NativeCrypto; r=snorp

This mismatch doesn't affect us with everything going through jemalloc,
but clang does warn about it, so let's get rid of the warning.

mozglue/android/NativeCrypto.cpp

@@ -126,7 +126,7 @@ extern "C" JNIEXPORT jbyteArray MOZ_JNICALL Java_org_mozilla_gecko_background_na
     env->SetByteArrayRegion(out, 0, 32, (jbyte*)digest);
   }
 
-  delete digest;
+  delete[] digest;
 
   return out;
 }