Created attachment 472702 [details]
example umlgraph source file that shows the issue

Description of problem:
Graphs created using umlgraph do not show arrow heads and tails.
I can correct this by adding dir=both to this line:

c3:p -> c4:p [taillabel="1..*", label="", headlabel="*", fontname="Helvetica", fontcolor="black", fontsize=10.0, color="black", arrowhead=none, arrowtail=ediamond];

so it looks like:

c3:p -> c4:p [dir=both, taillabel="1..*", label="", headlabel="*", fontname="Helvetica", fontcolor="black", fontsize=10.0, color="black", arrowhead=none, arrowtail=ediamond];

If I however compile an image using graphviz-2.12 which I still have on CentOS the graph looks ok without modifications.

In both cases, the command I use is:
dot -Tpng -o graph.png graph.dot

Version-Release number of selected component (if applicable):
5.2-3

How reproducible:
always

Steps to Reproduce:
1. 
javadoc -docletpath /usr/share/java/umlgraph.jar -doclet org.umlgraph.doclet.UmlGraph -private hazardmap.java
2.
dot -Tpng -o hazardmap.png graph.dot
3.
see output

Actual results:
no arrows in diagram

Expected results:
arrows expected

Additional info:
In communication with graphviz and umlgraph authors I found out this was due to a change in graphviz requiring the direction to be stated.
A just released version of umlgraph (5.4) fixes this issue, which I can confirm.
http://www.umlgraph.org/download.html