patch 8.1.1312: Coverity warning for using uninitialized variable

Problem:    Coverity warning for using uninitialized variable.
Solution:   Clear exarg_T.
diff --git a/src/channel.c b/src/channel.c
index aac8656..a29414f 100644
--- a/src/channel.c
+++ b/src/channel.c
@@ -2308,6 +2308,7 @@
 	exarg_T ea;
 
 	ch_log(channel, "Executing normal command '%s'", (char *)arg);
+	vim_memset(&ea, 0, sizeof(ea));
 	ea.arg = arg;
 	ea.addr_count = 0;
 	ea.forceit = TRUE; /* no mapping */
@@ -2318,6 +2319,7 @@
 	exarg_T ea;
 
 	ch_log(channel, "redraw");
+	vim_memset(&ea, 0, sizeof(ea));
 	ea.forceit = *arg != NUL;
 	ex_redraw(&ea);
 	showruler(FALSE);