[Pal/Linux-SGX] Remove python-crypto package from dependencies

.travis.yml

@@ -1,7 +1,7 @@
 language: c
 
 before_install:
-  - sudo apt-get install python-protobuf python-crypto
+  - sudo apt-get install python-protobuf
   - sudo apt-get install linux-headers-$(uname -r)
 
 before_script:

Jenkinsfiles/ubuntu-16.04.dockerfile

@@ -16,7 +16,6 @@ RUN apt-get update \
        libxml2-dev \
        net-tools \
        python \
-       python-crypto \
        python-protobuf \
        python3-minimal \
        texinfo \

Pal/src/host/Linux-SGX/signer/pal-sgx-get-token

@@ -5,7 +5,6 @@ import sys
 import struct
 import socket
 from google.protobuf import message as _message
-from Crypto.PublicKey import RSA
 import aesm_pb2
 
 """ Utilities """

README.md

@@ -47,17 +47,15 @@ Other distributions of 64-bit Linux can potentially, but the result is not
 guaranteed. If you find Graphene not working on other distributions, please
 contact us with a detailed bug report.
 
-The following packages are required for building Graphene: (can be installed
-with 'apt-get install')
-   - build-essential
-   - autoconf
-   - gawk
-   - gcc 4 or 5
-
-The following packages are also required for building Graphene for SGX (can
-be installed with 'apt-get install'):
-   - python-protobuf
-   - python-crypto
+Run the following command on Ubuntu to install dependencies for Graphene:
+
+    sudo apt-get install -y build-essential autoconf gawk
+
+
+For building Graphene for SGX, run the following command in addition:
+
+    sudo apt-get install -y python-protobuf
+
 
 To build the system, simply run the following commands in the root of the
 source tree: