shell32: Fix the character count passed to SearchPathW in SHELL_execute.

dlls/shell32/shlexec.c

@@ -1698,7 +1698,7 @@ BOOL SHELL_execute( LPSHELLEXECUTEINFOW sei, SHELL_ExecuteW32 execfunc )
 		buffer[idx] = '\0';
 
 		/*FIXME This finds directory paths if the targeted file name contains spaces. */
-		if (SearchPathW(*sei_tmp.lpDirectory? sei_tmp.lpDirectory: NULL, buffer, wszExe, sizeof(xlpFile), xlpFile, NULL))
+		if (SearchPathW(*sei_tmp.lpDirectory? sei_tmp.lpDirectory: NULL, buffer, wszExe, sizeof(xlpFile)/sizeof(xlpFile[0]), xlpFile, NULL))
 		{
 		    /* separate out command from parameter string */
 		    LPCWSTR p = space + 1;