Add -no_alt_chains option to apps to implement the new...

Add -no_alt_chains option to apps to implement the new X509_V_FLAG_NO_ALT_CHAINS flag. Using this option means that when building certificate chains, the first chain found will be the one used. Without this flag, if the first chain found is not trusted then we will keep looking to see if we can build an alternative chain instead.

Reviewed-by: Dr. Stephen Henson <steve@openssl.org>
Reviewed-by: Kurt Roeckx <kurt@roeckx.be>

Conflicts:
	apps/cms.c
	apps/ocsp.c
	apps/s_client.c
	apps/s_server.c
	apps/smime.c
	apps/verify.c