Parsing grammar.parseString dont work correct with '='

[helodron]

Hi.

After patch http://bazaar.launchpad.net/~graphite-dev/graphite/trunk/revision/970/webapp/graphite/render/grammar.py, parsing strings with '=' dont work correct:

>>>string2 = 'maxSeries(group(sumSeries(one_min.tools._hosts.{front*,soap*,scripts*,back*}.profile.Perl::DBTools::_sth_execute.db=dict~*.el), sumSeries(one_min.tools._hosts.{front*,soap*,scripts*,back*}.trace.db:*.dict*.all_ela)))'

>>> grammar.parseString(string2)

([(['maxSeries'], {'pathExpression': [('maxSeries', 0)]})], {'expression': [((['maxSeries'], {'pathExpression': [('maxSeries', 0)]}), 0)]})

OLD: validMetricChars = alphanums + r'''!#$%&"'*+-.:;<=>?@[\]^_`|~'''

NEW: symbols = '''(){},=.'"\\'''
NEW: validMetricChars = ''.join((set(printables) - set(symbols)))

Why removed "=" ?