BUG/MEDIUM: cli: Set SE_FL_EOI flag for '_getsocks' and 'quit' commands

An applet must never set SE_FL_EOS flag without SE_FL_EOI or SE_FL_ERROR
flags. Here, SE_FL_EOI flag was missing for "quit" or "_getsocks"
commands. Indeed, these commands are terminal.

This bug triggers a BUG_ON() recently added.

This patch is related to the issue #2107. It is 2.8-specific. No backport
needed.
diff --git a/src/cli.c b/src/cli.c
index 1b4276f..0849cbe 100644
--- a/src/cli.c
+++ b/src/cli.c
@@ -2172,6 +2172,7 @@
 		ha_warning("Cannot make the unix socket non-blocking\n");
 		goto out;
 	}
+	se_fl_set(appctx->sedesc, SE_FL_EOI);
 	appctx->st0 = CLI_ST_END;
 	free(cmsgbuf);
 	free(tmpbuf);
@@ -2186,9 +2187,11 @@
 	else if (*args[0] == 'p')
 		/* prompt */
 		appctx->st1 ^= APPCTX_CLI_ST1_PROMPT;
-	else if (*args[0] == 'q')
+	else if (*args[0] == 'q') {
 		/* quit */
+		se_fl_set(appctx->sedesc, SE_FL_EOI);
 		appctx->st0 = CLI_ST_END;
+	}
 
 	return 1;
 }