Migrate ff, group, pairing, and bellman to rand 0.6

pairing/src/bls12_381/fq.rs

@@ -1173,7 +1173,9 @@ fn test_neg_one() {
 }
 
 #[cfg(test)]
-use rand::{SeedableRng, XorShiftRng};
+use rand_core::SeedableRng;
+#[cfg(test)]
+use rand_xorshift::XorShiftRng;
 
 #[test]
 fn test_fq_repr_ordering() {

pairing/src/bls12_381/fq12.rs

@@ -147,7 +147,9 @@ impl Field for Fq12 {
 }
 
 #[cfg(test)]
-use rand::{SeedableRng, XorShiftRng};
+use rand_core::SeedableRng;
+#[cfg(test)]
+use rand_xorshift::XorShiftRng;
 
 #[test]
 fn test_fq12_mul_by_014() {

pairing/src/bls12_381/fq2.rs

@@ -877,7 +877,9 @@ fn test_fq2_legendre() {
 }
 
 #[cfg(test)]
-use rand::{SeedableRng, XorShiftRng};
+use rand_core::SeedableRng;
+#[cfg(test)]
+use rand_xorshift::XorShiftRng;
 
 #[test]
 fn test_fq2_mul_nonresidue() {

pairing/src/bls12_381/fq6.rs

@@ -301,7 +301,9 @@ impl Field for Fq6 {
 }
 
 #[cfg(test)]
-use rand::{SeedableRng, XorShiftRng};
+use rand_core::SeedableRng;
+#[cfg(test)]
+use rand_xorshift::XorShiftRng;
 
 #[test]
 fn test_fq6_mul_nonresidue() {

pairing/src/bls12_381/fr.rs

@@ -6,7 +6,9 @@ use ff::{Field, PrimeField, PrimeFieldDecodingError, PrimeFieldRepr};
 pub struct Fr(FrRepr);
 
 #[cfg(test)]
-use rand::{SeedableRng, XorShiftRng};
+use rand_core::SeedableRng;
+#[cfg(test)]
+use rand_xorshift::XorShiftRng;
 
 #[test]
 fn test_fr_repr_ordering() {