avformat/httpauth: Add space after commas in HTTP/RTSP auth header

This fixes access to Grandstream cameras, which return 401 to ffmpeg
otherwise.
VLC sends Authorization: header with spaces between parameters, and it
is known to work with Grandstream devices and broad range of other HTTP
and RTSP servers, so author considers switching to such behaviour safe.
Just for record - RFC 2617 (HTTP Auth) does not specify the need in
spaces, so this is not a bug of FFmpeg.

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavformat/httpauth.c

@@ -220,21 +220,21 @@ static char *make_digest_auth(HTTPAuthState *state, const char *username,
 
     /* TODO: Escape the quoted strings properly. */
     av_strlcatf(authstr, len, "username=\"%s\"",   username);
-    av_strlcatf(authstr, len, ",realm=\"%s\"",     state->realm);
-    av_strlcatf(authstr, len, ",nonce=\"%s\"",     digest->nonce);
-    av_strlcatf(authstr, len, ",uri=\"%s\"",       uri);
-    av_strlcatf(authstr, len, ",response=\"%s\"",  response);
+    av_strlcatf(authstr, len, ", realm=\"%s\"",     state->realm);
+    av_strlcatf(authstr, len, ", nonce=\"%s\"",     digest->nonce);
+    av_strlcatf(authstr, len, ", uri=\"%s\"",       uri);
+    av_strlcatf(authstr, len, ", response=\"%s\"",  response);
 
     // we are violating the RFC and use "" because all others seem to do that too.
     if (digest->algorithm[0])
-        av_strlcatf(authstr, len, ",algorithm=\"%s\"",  digest->algorithm);
+        av_strlcatf(authstr, len, ", algorithm=\"%s\"",  digest->algorithm);
 
     if (digest->opaque[0])
-        av_strlcatf(authstr, len, ",opaque=\"%s\"", digest->opaque);
+        av_strlcatf(authstr, len, ", opaque=\"%s\"", digest->opaque);
     if (digest->qop[0]) {
-        av_strlcatf(authstr, len, ",qop=\"%s\"",    digest->qop);
-        av_strlcatf(authstr, len, ",cnonce=\"%s\"", cnonce);
-        av_strlcatf(authstr, len, ",nc=%s",         nc);
+        av_strlcatf(authstr, len, ", qop=\"%s\"",    digest->qop);
+        av_strlcatf(authstr, len, ", cnonce=\"%s\"", cnonce);
+        av_strlcatf(authstr, len, ", nc=%s",         nc);
     }
 
     av_strlcatf(authstr, len, "\r\n");