Truncate vendor snapshot header glob list after filtering it

Test: m checkbuild
Change-Id: I4847bff5c03844194a9a80e8cb24a60694db6208
diff --git a/cc/library.go b/cc/library.go
index 73ed969..29a3c69 100644
--- a/cc/library.go
+++ b/cc/library.go
@@ -481,6 +481,7 @@
 			}
 			j++
 		}
+		glob = glob[:j]
 	}
 
 	// Collect generated headers