Updated to latest aws-c-io to pick up a windows security fix. (aws#74)

Author: JonathanHenson

aws-common-runtime/CMakeLists.txt

@@ -27,7 +27,7 @@ if (UNIX AND NOT APPLE)
 endif()
 
 set(AWS_C_IO_URL "https://github.com/awslabs/aws-c-io.git")
-set(AWS_C_IO_SHA "v0.4.16")
+set(AWS_C_IO_SHA "v0.4.17")
 include(BuildAwsCIO)
 
 set(AWS_C_COMPRESSION_URL "https://github.com/awslabs/aws-c-compression.git")