git log --graph: print '*' for all commits, including merges

Previously, merge commits were printed with 'M' instead of '*'.  This
had the potential to confuse users when not all parents of the merge
commit were included in the log output.

As Junio has pointed out, merge commits can almost always be easily
identified from the log message, anyway.

Signed-off-by: Adam Simpkins <adam@adamsimpkins.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

graph.c

@@ -679,20 +679,6 @@ static void graph_output_commit_char(struct git_graph *graph, struct strbuf *sb)
 		return;
 	}
 
-	/*
-	 * Print 'M' for merge commits
-	 *
-	 * Note that we don't check graph->num_parents to determine if the
-	 * commit is a merge, since that only tracks the number of
-	 * "interesting" parents.  We want to print 'M' for merge commits
-	 * even if they have less than 2 interesting parents.
-	 */
-	if (graph->commit->parents != NULL &&
-	    graph->commit->parents->next != NULL) {
-		strbuf_addch(sb, 'M');
-		return;
-	}
-
 	/*
 	 * Print '*' in all other cases
 	 */