Tweak travis targets and dates

Just trying to get a PR to land...

Author: alexcrichton

.travis.yml

@@ -61,36 +61,36 @@ matrix:
            IMAGE=cross
     - env: TARGET=mips64-unknown-linux-gnuabi64
            IMAGE=cross
-      rust: beta
+      rust: beta-2017-03-03
     - env: TARGET=mips64el-unknown-linux-gnuabi64
            IMAGE=cross
-      rust: beta
+      rust: beta-2017-03-03
     - env: TARGET=s390x-unknown-linux-gnu
            IMAGE=cross
-      rust: beta
+      rust: beta-2017-03-03
     - env: TARGET=powerpc-unknown-linux-gnu
            IMAGE=cross
-      rust: beta
+      rust: beta-2017-03-03
     - env: TARGET=powerpc64-unknown-linux-gnu
            IMAGE=cross
-      rust: beta
+      rust: beta-2017-03-03
     - env: TARGET=powerpc64le-unknown-linux-gnu
            IMAGE=cross
-      rust: beta
+      rust: beta-2017-03-03
 
     # beta/nightly builds
     - env: TARGET=x86_64-unknown-linux-gnu
            ALT=i686-unknown-linux-gnu
            IMAGE=dist
            MAKE_TARGETS="test distcheck doc install uninstall"
            DEPLOY=0
-      rust: beta
+      rust: beta-2017-03-03
     - env: TARGET=x86_64-unknown-linux-gnu
            ALT=i686-unknown-linux-gnu
            IMAGE=dist
            MAKE_TARGETS="test distcheck doc install uninstall"
            DEPLOY=0
-      rust: nightly
+      rust: nightly-2017-03-03
 
   exclude:
     - rust: stable

appveyor.yml

@@ -30,7 +30,7 @@ install:
 
   # FIXME(#3394) use master rustup
   - curl -sSfO https://static.rust-lang.org/rustup/archive/0.6.5/x86_64-pc-windows-msvc/rustup-init.exe
-  - rustup-init.exe -y --default-host x86_64-pc-windows-msvc --default-toolchain nightly
+  - rustup-init.exe -y --default-host x86_64-pc-windows-msvc --default-toolchain nightly-2017-03-03
   - set PATH=%PATH%;C:\Users\appveyor\.cargo\bin
   - if NOT "%TARGET%" == "x86_64-pc-windows-msvc" rustup target add %TARGET%
   - if defined OTHER_TARGET rustup target add %OTHER_TARGET%