Feature gate some stuff in Xor test to prevent warnings

UserAB1236872 · UserAB1236872 · commit 5531b4417e37 · 2018-01-22T03:15:33.000-08:00
diff --git a/src/prng/xorshift.rs b/src/prng/xorshift.rs
@@ -119,6 +119,7 @@ impl Rand for XorShiftRng {
 
 #[cfg(test)]
 mod tests {
+    #[cfg(feature="serde-1")]
     use {Rng, SeedableRng};
 
     #[cfg(feature="serde-1")]
