Adjust regexes for new robot version

Keep newer versions of robot from trying to interpret the following as a
dictionary entry reference.

${component_name}[0-9]

Should be:

${component_name}\[0-9]

Change-Id: If4d67c9c7147bd27c9b9ca133bb93dd729321fa1
Signed-off-by: Michael Walsh <micwalsh@us.ibm.com>
diff --git a/tests/test_sensors.robot b/tests/test_sensors.robot
index 05840c6..3e99250 100644
--- a/tests/test_sensors.robot
+++ b/tests/test_sensors.robot
@@ -51,7 +51,7 @@
     [Documentation]  Get the system component.
     [Arguments]    ${type}
     ${list}=    Get Dictionary Keys    ${SYSTEM_INFO}
-    ${resp}=    Get Matches    ${list}    regexp=^.*[0-9a-z_].${type}[0-9]*$
+    ${resp}=    Get Matches    ${list}    regexp=^.*[0-9a-z_].${type}\[0-9]*$
     ${url}=    Get From List    ${resp}    0
     [Return]    ${url}