Fix problem where orphan section is treated as a KEEP section.

2016-12-01  Cary Coutant  <ccoutant@gmail.com>

gold/
	PR gold/20717
	* script-sections.cc (Script_sections): Set *keep to false when
	no match.

diff --git a/gold/script-sections.cc b/gold/script-sections.cc
index bf25391..f35ecc1 100644
--- a/gold/script-sections.cc
+++ b/gold/script-sections.cc
@@ -3538,6 +3538,7 @@ Script_sections::output_section_name(
 
   *output_section_slot = NULL;
   *psection_type = Script_sections::ST_NONE;
+  *keep = false;
 
   return section_name;
 }