Update GET request header to Content-Type=application/json

Looks like recent bmcweb changes blocks the GET request for
Content-Type=application/octet-stream

Change-Id: I4e66c4d10d99c902884530a2446445cc4abbc040
Signed-off-by: George Keishing <gkeishin@in.ibm.com>
diff --git a/lib/rest_client.robot b/lib/rest_client.robot
index dfee34a..d8e9590 100644
--- a/lib/rest_client.robot
+++ b/lib/rest_client.robot
@@ -43,8 +43,7 @@
     Initialize OpenBMC  ${timeout}  quiet=${quiet}
 
     ${base_uri}=    Catenate    SEPARATOR=    ${DBUS_PREFIX}    ${uri}
-    ${headers}=  Create Dictionary  Content-Type=application/octet-stream
-    ...  X-Auth-Token=${XAUTH_TOKEN}  Accept=application/octet-stream
+    ${headers}=  Create Dictionary  X-Auth-Token=${XAUTH_TOKEN}  Accept=application/json
     Set To Dictionary  ${kwargs}  headers  ${headers}
     Run Keyword If  '${quiet}' == '${0}'  Log Request  method=Get
     ...  base_uri=${base_uri}  args=&{kwargs}
@@ -362,7 +361,7 @@
     Initialize OpenBMC  ${timeout}  quiet=${quiet}
     ${base_uri}=  Catenate  SEPARATOR=  ${DBUS_PREFIX}  ${uri}
     ${headers}=  Create Dictionary  Content-Type=application/octet-stream
-    ...  X-Auth-Token=${XAUTH_TOKEN}  Accept=application/octet-stream
+    ...  X-Auth-Token=${XAUTH_TOKEN}  Accept=application/json
     Set To Dictionary  ${kwargs}  headers  ${headers}
     Run Keyword If  '${quiet}' == '${0}'  Log Request  method=Post
     ...  base_uri=${base_uri}  args=&{kwargs}