address review comment

Author: kiszk

dev/run-tests.py

@@ -254,10 +254,8 @@ def kill_zinc_on_port(zinc_port):
     Kill the Zinc process running on the given port, if one exists.
     """
     cmd = "%s -P |grep %s | grep LISTEN | awk '{ print $2; }' | xargs kill"
-    try:
-        subprocess.check_call(cmd % ("lsof", zinc_port), shell=True)
-    except:
-        subprocess.check_call(cmd % ("/usr/sbin/lsof", zinc_port), shell=True)
+    lsof_exe = which("lsof")
+    subprocess.check_call(cmd % (lsof_exe if lsof_exe else "/usr/sbin/lsof", zinc_port), shell=True)
 
 
 def exec_maven(mvn_args=()):