Exception while logging error in JDraw parser

[cpascual]

During the investigation for #1077 I found that jdraw_parser fails to report the parsing issues due to a bug in its logging mechanism.

To reproduce, run the following snippet:

import taurus
taurus.setLogLevel(taurus.Trace)
from taurus.qt.qtgui.application import TaurusApplication
from taurus.qt.qtgui.graphic.jdraw import TaurusJDrawSynopticsView

app = TaurusApplication(cmd_line_parser=None)
w = TaurusJDrawSynopticsView()
fname = "unsuported.jdw"
w.setModel(fname)

where unsupported.jdw contains:

JDFile v11 {
  Global {
  }
  JDasdasdBar {
    summit:385,70,422,105
    origin:437,57
    fillStyle:1
    name:"tango:sys/tg_test/1/state"
  }
}

In the result, we can see the following debug trace:

MainThread     WARNING  2020-02-26 15:37:22,849 JDraw Parser: Failed to parse /tmp/bug1077_log.jdw
MainThread     DEBUG    2020-02-26 15:37:22,849 JDraw Parser: Details:
Traceback (most recent call last):
  File "/nfs/home/cpascual/src/taurus/lib/taurus/qt/qtgui/graphic/jdraw/jdraw_parser.py", line 352, in parse
    res = yacc.parse(f.read())
  File "/home/cpascual/miniconda/envs/py3qt5/lib/python3.7/site-packages/ply/yacc.py", line 333, in parse
    return self.parseopt_notrack(input, lexer, debug, tracking, tokenfunc)
  File "/home/cpascual/miniconda/envs/py3qt5/lib/python3.7/site-packages/ply/yacc.py", line 1201, in parseopt_notrack
    tok = call_errorfunc(self.errorfunc, errtoken, self)
  File "/home/cpascual/miniconda/envs/py3qt5/lib/python3.7/site-packages/ply/yacc.py", line 192, in call_errorfunc
    r = errorfunc(token)
  File "/nfs/home/cpascual/src/taurus/lib/taurus/qt/qtgui/graphic/jdraw/jdraw_parser.py", line 108, in p_error
    p.lexer.log.error("[%d]: Syntax error in input [%s]" %
AttributeError: 'Lexer' object has no attribute 'log'