[COMMITTED] Fix comments in _dl_dst_count and _dl_dst_substitute.

[Carlos O'Donell <carlos at redhat dot com>]

DJ Delorie <dj@redhat.com> pointed out some obvious comment mistakes
in the DST changes. Thanks DJ!

---
The comments in _dl_dst_count is adjusted to match what the code does
which is count DSTs from the start of the string. With the removal of
DL_DST_COUNT we no longer accept an input that starts at the first $.

In _dl_dst_substitute we adjust the comment to indicate that both
conditions must be true for the SUID/SGID $ORIGIN exception.
---
 ChangeLog     |  3 +++
 elf/dl-load.c | 14 ++++++++------
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index f3ba045896..9fbd48d848 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,8 @@
 2018-06-12  Carlos O'Donell  <carlos@redhat.com>
 
+	* elf/dl-load (_dl_dst_substitute): Correct comment.
+	(_dl_dst_count): Likewise.
+
 	* nptl/pthread_mutex_timedlock.c (__pthread_mutex_timedlock): Call
 	lll_futex_timed_wait.
 
diff --git a/elf/dl-load.c b/elf/dl-load.c
index e81601f36d..09185ab68d 100644
--- a/elf/dl-load.c
+++ b/elf/dl-load.c
@@ -219,11 +219,11 @@ is_dst (const char *input, const char *ref)
     return rlen;
 }
 
-/* INPUT is the start of a DST sequence at the first '$' occurrence.
-   If there is a DST we call into _dl_dst_count to count the number of
-   DSTs.  We count all known DSTs regardless of __libc_enable_secure;
-   the caller is responsible for enforcing the security of the
-   substitution rules (usually _dl_dst_substitute).  */
+/* INPUT should be the start of a path e.g DT_RPATH or name e.g.
+   DT_NEEDED.  The return value is the number of known DSTs found.  We
+   count all known DSTs regardless of __libc_enable_secure; the caller
+   is responsible for enforcing the security of the substitution rules
+   (usually _dl_dst_substitute).  */
 size_t
 _dl_dst_count (const char *input)
 {
@@ -292,7 +292,9 @@ _dl_dst_substitute (struct link_map *l, const char *input, char *result)
 		   * $ORIGIN appears as the first path element, and is
 		     the only string in the path or is immediately
 		     followed by a path separator and the rest of the
-		     path.
+		     path,
+
+		   and ...
 
 		   * The path is rooted in a trusted directory.
 
-- 
2.14.4

Cheers,
Carlos.