per #1713, added instructions to set METPLOTPY_BASE via [user_env_var…

…s] in the default METplus config file upon install if necessary

parm/metplus_config/defaults.conf

@@ -107,3 +107,14 @@ LOG_DEBUG_LINE_FORMAT = {LOG_LINE_FORMAT}
 LOG_INFO_LINE_FORMAT = %(asctime)s.%(msecs)03d %(name)s %(levelname)s: %(message)s
 
 LOG_LINE_DATE_FORMAT = %m/%d %H:%M:%S
+
+###############################################################################
+# METplotpy Installation Location                                             #
+#   * Uncomment and set METPLOTPY_BASE to the path where                      #
+#     METplotpy is installed. This is not necessary if METplotpy will not be  #
+#     used or if METPLOTPY_BASE is set in the user's environment.             #
+###############################################################################
+
+[user_env_vars]
+
+#METPLOTPY_BASE= /path/to/METplotpy