patch 8.0.1672: error during completion causes command to be cancelled

Problem:    Error during completion causes command to be cancelled.
Solution:   Reset did_emsg before waiting for another character. (Tom M.)

src/ex_getln.c

@@ -426,6 +426,10 @@ getcmdline(
 #endif
 	quit_more = FALSE;	/* reset after CTRL-D which had a more-prompt */
 
+	did_emsg = FALSE;	/* There can't really be a reason why an error
+				   that occurs while typing a command should
+				   cause the command not to be executed. */
+
 	cursorcmd();		/* set the cursor on the right spot */
 
 	/* Get a character.  Ignore K_IGNORE and K_NOP, they should not do