x509parse_crt() now better handles PEM error situations

Because of new pem_read_buffer() handling of when it writes use_len,
x509parse_crt() is able to better handle situations where a PEM blob
results in an error but the other blobs can still be parsed.
(cherry picked from commit 6417186365f4a73a719fff754fefe8edcef2bc28)

Conflicts:
	ChangeLog
diff --git a/ChangeLog b/ChangeLog
index 5618789..4e9fb7c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -4,6 +4,9 @@
 Changes
    * HAVEGE random generator disabled by default
 
+Bugfix
+   * x509parse_crt() now better handles PEM error situations
+
 = Version 1.1.6 released on 2013-03-11
 Bugfix
    * Fixed net_bind() for specified IP addresses on little endian systems