lava-submit.py: should handle the exceptions while changing the test list

Signed-off-by: Ricardo Salveti de Araujo <ricardo.salveti@linaro.org>
diff --git a/lava-submit.py b/lava-submit.py
index 0e78b9f..185759f 100755
--- a/lava-submit.py
+++ b/lava-submit.py
@@ -113,12 +113,18 @@
 
     # removing bluetooth and wifi for devices that don't support it
     if args.device_type in ['beaglexm', 'vexpress', 'mx53loco']:
-        tests.remove('bluetooth-enablement')
-        tests.remove('wifi-enablement')
+        try:
+            tests.remove('bluetooth-enablement')
+            tests.remove('wifi-enablement')
+        except ValueError:
+            pass
 
     # vexpress doesn't support PM, so disable pwrmgmt
     if args.device_type in ['vexpress']:
-        tests.remove('pwrmgmt')
+        try:
+            tests.remove('pwrmgmt')
+        except ValueError:
+            pass
 
     job = get_job(args.job_name, args.device_type, args.img_url, tests)