patch 9.1.1273: Coverity warns about using uninitialized value

Problem:  Coverity warns about using uninitialized value
          (after 9.1.1270).
Solution: Put an empty string in "buf" when allocation fails (zeertzjq).

closes: #17040

Signed-off-by: zeertzjq <zeertzjq@outlook.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>

src/buffer.c

@@ -4037,6 +4037,8 @@ maketitle(void)
 		    vim_strncpy(buf, p, SPACE_FOR_FNAME);
 		    vim_free(p);
 		}
+		else
+		    STRCPY(buf, "");
 	    }
 
 #ifdef FEAT_TERMINAL

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1273,
 /**/
     1272,
 /**/