spelling mistake in arguments to build nghttp apps

At least we should make sure that the OCSP response is targeted to the
expected certificate.  This is important because we pass the file path
to the external script, and if the file is replaced because of
renewal, and nghttpx has not reloaded its configuration, the
certificate nghttpx has loaded and the one included in the file
differ.  Verifying the OCSP response detects this, and avoids to send
wrong OCSP response.

Call ERR_clear_error() before the OpenSSL function if we use
SSL_get_error() to examine error stack.

Compile with --disable-assert

nghttpx: Run OCSP at startup

nghttp2_session: Allow for compiling library with -DNDEBUG set

With --ocsp-startup option, nghttpx starts accepting connections after
initial attempts to get OCSP responses finish.  It does not matter
some of the attempts fail.  This feature is useful if OCSP responses
must be available before accepting connections.

Update docs

This commit adds wildcard path matching.  If path pattern given in
backend option ends with "*", it is considered as wildcard path.  "*"
must match at least one character.  All paths which include wildcard
path without last "*" as prefix, and are strictly longer than wildcard
path without last "*" are matched.