Fix for cpu inventory path for Get_a_Property test case

Why the test case failing:
   - The URL for CPU is not same for Barreleye and Palmetto.

This fix includes:
   - Enumerates the inventory to find cpu URL path
   - Removed this test from skip list
   - Added keywork in utils.robot to get url paths ending
     particular string

Resolves openbmc/openbmc-test-automation#208

Change-Id: I59c1969ad01a6aee88af99aa7ccc7a46359584f1
Signed-off-by: Rahul Maheshwari <rahulmaheshwari@in.ibm.com>
diff --git a/tests/test_obmcrest.robot b/tests/test_obmcrest.robot
index 5a6dfb6..10eb871 100644
--- a/tests/test_obmcrest.robot
+++ b/tests/test_obmcrest.robot
@@ -24,8 +24,10 @@
 
 Get a Property
     [Tags]  Get_a_Property
-    ${resp}=   Read Attribute      /org/openbmc/inventory/system/chassis/motherboard/cpu0      is_fru
-    Should Be Equal    ${resp}     ${1}
+    ${url_list}=   Get Endpoint Paths   ${OPENBMC_BASE_URI}inventory   cpu
+    ${url}=   Get From List   ${url_list}   0
+    ${resp}=   Read Attribute   ${url}   is_fru
+    Should Be Equal   ${resp}   ${1}
 
 Get a null Property
     ${resp}=    OpenBMC Get Request    /org/openbmc/inventory/attr/is_fru