nightly-2019-01-10 is current busted, pinning to 2019-01-09 for now

Change-Id: I227a16fc576ecc84f2a72635a1395601c5730c7f
diff --git a/.travis.yml b/.travis.yml
index 6f98dd7..e58355c 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,7 +5,7 @@
 language: rust
 cache: cargo
 rust:
-  - nightly
+  - nightly-2019-01-09
 
 env:
   global:
diff --git a/appveyor.yml b/appveyor.yml
index 0348f0d..87a08fd 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -12,11 +12,11 @@
   matrix:
     # Rust - Nightly
     - TARGET: i686-pc-windows-gnu
-      RUST_VERSION: nightly
+      RUST_VERSION: nightly-2019-01-09
       BITS: 32
       MSYS2: 1
     - TARGET: x86_64-pc-windows-msvc
-      RUST_VERSION: nightly
+      RUST_VERSION: nightly-2019-01-09
       BITS: 64
 
 install: