Adds test for odd bit length RSA key size

Also tidy up ChangeLog following review.
diff --git a/library/rsa.c b/library/rsa.c
index 19abc7f..9fc80cd 100644
--- a/library/rsa.c
+++ b/library/rsa.c
@@ -117,11 +117,15 @@
                                 f_rng, p_rng ) );
 
         if( nbits % 2 )
+        {
             MBEDTLS_MPI_CHK( mbedtls_mpi_gen_prime( &ctx->Q, ( nbits >> 1 ) + 1, 0,
                                 f_rng, p_rng ) );
+        }
         else
+        {
             MBEDTLS_MPI_CHK( mbedtls_mpi_gen_prime( &ctx->Q, nbits >> 1, 0,
                                 f_rng, p_rng ) );
+        }
 
         if( mbedtls_mpi_cmp_mpi( &ctx->P, &ctx->Q ) == 0 )
             continue;