config: drop cf validity check in get_next_char()

The global variable cf is set with an initialized value in all codepaths before
calling this function.

The complete call graph looks like this:

  git_config_from_file
    -> do_config_from
      -> git_parse_file
        -> get_next_char
        -> get_value
            -> get_next_char
            -> parse_value
                -> get_next_char
        -> get_base_var
            -> get_next_char
            -> get_extended_base_var
                -> get_next_char

The variable is initialized in do_config_from.
Signed-off-by: NHeiko Voigt <hvoigt@hvoigt.net>
Acked-by: NJeff King <peff@peff.net>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

config.c

@@ -169,26 +169,23 @@ int git_config_from_parameters(config_fn_t fn, void *data)
 static int get_next_char(void)
 {
 	int c;
-	FILE *f;
+	FILE *f = cf->f;
 
-	c = '\n';
-	if (cf && ((f = cf->f) != NULL)) {
+	c = fgetc(f);
+	if (c == '\r') {
+		/* DOS like systems */
 		c = fgetc(f);
-		if (c == '\r') {
-			/* DOS like systems */
-			c = fgetc(f);
-			if (c != '\n') {
-				ungetc(c, f);
-				c = '\r';
-			}
-		}
-		if (c == '\n')
-			cf->linenr++;
-		if (c == EOF) {
-			cf->eof = 1;
-			c = '\n';
+		if (c != '\n') {
+			ungetc(c, f);
+			c = '\r';
 		}
 	}
+	if (c == '\n')
+		cf->linenr++;
+	if (c == EOF) {
+		cf->eof = 1;
+		c = '\n';
+	}
 	return c;
 }