jogl: indent trace statements in the Trace pipelines when we hit glBegin

The indent was being reduced on glEnd/glEndList but was never being incremented.
The intent appeared to be to indent all statements between glBEgin/glEnd pairs to
show the nested context of those calls.  Add the increment after printing the glBegin
trace statement.

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>