Pin to a specific SGX nightly

Author: jack-fortanix

.travis.yml

@@ -22,6 +22,7 @@ env:
     # Pinned to this particular nightly version because of core_io. This can be
     # re-pinned whenever core_io is updated to the latest nightly.
     - CORE_IO_NIGHTLY=nightly-2019-07-01
+    - SGX_NIGHTLY=nightly-2019-07-11
     - LLVM_CONFIG_PATH=llvm-config-3.8
 matrix:
   include:

ct.sh

@@ -23,7 +23,9 @@ elif [ $TOOLCHAIN = "coreio_nightly" ]; then
     cargo +$CORE_IO_NIGHTLY test --no-default-features --features core_io,rdrand
 
 elif [ $TOOLCHAIN = "sgx" ]; then
-    rustup toolchain add nightly
-    cargo +nightly test --no-run --target=x86_64-fortanix-unknown-sgx --features=sgx --no-default-features
+
+    rustup toolchain add $SGX_NIGHTLY
+    rustup target add --toolchain $SGX_NIGHTLY x86_64-fortanix-unknown-sgx
+    cargo +$SGX_NIGHTLY test --no-run --target=x86_64-fortanix-unknown-sgx --features=sgx --no-default-features
 
 fi