Simplify VCH management API metadata test cases (#8150)

Previously, it was necessary to retry Get Version due to the potential
for a race between server initialization and test execution. Now that
the Start VIC Machine Server keyword waits for the server to start
(280704f), this race is no longer possible. Simplify the test code
accordingly.

Additionally, eliminate duplicaton of the service name between setup
and diagnostic keywords by defining a variable.

Author: zjs

tests/resources/Group23-VIC-Machine-Service-Util.robot

@@ -23,6 +23,7 @@ ${RC}            The return code of the last curl invocation
 ${OUTPUT}        The output of the last curl invocation
 ${STATUS}        The HTTP status of the last curl invocation
 
+${VIC_MACHINE_SERVER_BIN}    ./bin/vic-machine-server
 ${VIC_MACHINE_SERVER_LOG}    vic-machine-server.log
 ${SERVING_AT_TEXT}           Serving vic machine at
 
@@ -32,7 +33,7 @@ Start VIC Machine Server
     ${dir_name}=  Evaluate  'group23_log_dir' + str(random.randint(1000,9999))  modules=random
     Set Suite Variable    ${SERVER_LOG_FILE}    ${dir_name}/${VIC_MACHINE_SERVER_LOG}
 
-    ${handle}=    Start Process    ./bin/vic-machine-server --scheme http --log-directory ${dir_name}/    shell=True    cwd=/go/src/github.com/vmware/vic
+    ${handle}=    Start Process    ${VIC_MACHINE_SERVER_BIN} --scheme http --log-directory ${dir_name}/    shell=True    cwd=/go/src/github.com/vmware/vic
     Set Suite Variable    ${SERVER_HANDLE}    ${handle}
     Process Should Be Running    ${handle}
     Sleep  5sec

tests/test-cases/Group23-VIC-Machine-Service/23-01-Metadata.robot

@@ -23,12 +23,7 @@ Default Tags
 
 *** Keywords ***
 Get Version
-    ${out}=  Run  netstat -l | grep 1337
-    Log  ${out}
-    ${out}=  Run  ps aux | grep vic-machine-server
-    Log  ${out}
     Get Path    version
-    Verify Return Code
 
 Get Hello
     Get Path    hello
@@ -44,8 +39,9 @@ Verify Hello
 
 *** Test Cases ***
 Get Version
-    Wait Until Keyword Succeeds  5x  1s  Get Version
+    Get Version
 
+    Verify Return Code
     Verify Status Ok
     Verify Version