opt-suggestions.c: fix minor memory leak

gcc/ChangeLog:
	* opt-suggestions.c (option_proposer::build_option_suggestions):
	Release "option_values".

From-SVN: r264698

gcc/ChangeLog

 2018-09-28  David Malcolm  <dmalcolm@redhat.com>
 
+	* opt-suggestions.c (option_proposer::build_option_suggestions):
+	Release	"option_values".
+
+2018-09-28  David Malcolm  <dmalcolm@redhat.com>
+
 	* coverage.c (get_coverage_counts): Convert problem-reporting dump
 	messages from MSG_OPTIMIZED_LOCATIONS to MSG_MISSED_OPTIMIZATION.
 	* dumpfile.c (kind_as_string): New function.

gcc/opt-suggestions.c

@@ -152,6 +152,7 @@ option_proposer::build_option_suggestions (const char *prefix)
 			  free (with_arg);
 			}
 		    }
+		  option_values.release ();
 		}
 	      else
 		add_misspelling_candidates (m_option_suggestions, option,