obs-outputs: fix RTMP reconnect (fixes obsproject#2865)

Bug is caused by the internal connection variables not being reset on reconnect, leading OBS to both be unable to parse valid packets from and send valid packets to the remote end.
This commit splits RTMP_Init off into a new RTMP_Reset function, which resets these internal variables without re-initing the rest of the library.
The original RTMP_Init calls the new function, perfectly preserving the old behaviour while adding a new reset function to address the issue with.

plugins/obs-outputs/librtmp/rtmp.c

@@ -463,6 +463,17 @@ RTMP_Init(RTMP *r)
 {
     memset(r, 0, sizeof(RTMP));
     r->m_sb.sb_socket = -1;
+    RTMP_Reset(r);
+
+#ifdef CRYPTO
+    RTMP_TLS_Init(r);
+#endif
+
+}
+
+void
+RTMP_Reset(RTMP * r)
+{
     r->m_inChunkSize = RTMP_DEFAULT_CHUNKSIZE;
     r->m_outChunkSize = RTMP_DEFAULT_CHUNKSIZE;
     r->m_bSendChunkSizeInfo = 1;
@@ -476,11 +487,6 @@ RTMP_Init(RTMP *r)
     r->Link.nStreams = 0;
     r->Link.timeout = 30;
     r->Link.swfAge = 30;
-
-#ifdef CRYPTO
-    RTMP_TLS_Init(r);
-#endif
-
 }
 
 void

plugins/obs-outputs/librtmp/rtmp.h

@@ -506,6 +506,7 @@ extern "C"
     int RTMP_ClientPacket(RTMP *r, RTMPPacket *packet);
 
     void RTMP_Init(RTMP *r);
+    void RTMP_Reset(RTMP *r);
     void RTMP_Close(RTMP *r);
     RTMP *RTMP_Alloc(void);
     void RTMP_TLS_Free(RTMP *r);

plugins/obs-outputs/rtmp-stream.c

@@ -969,8 +969,9 @@ static int try_connect(struct rtmp_stream *stream)
 
 	info("Connecting to RTMP URL %s...", stream->path.array);
 
-	// this should have been called already by rtmp_stream_create
-	//RTMP_Init(&stream->rtmp);
+	// on reconnect we need to reset the internal variables of librtmp
+        // otherwise the data sent/received will not parse correctly on the other end
+	RTMP_Reset(&stream->rtmp);
 
 	// since we don't call RTMP_Init above, there's no other good place
 	// to reset this as doing it in RTMP_Close breaks the ugly RTMP