Configparser loads entire ENV space

[bari12]

Motivation

For probably historic reasons our config parser (For rucio.cfg) also loads the entire ENV space into the config parser. This causes certain issues at a few sites, since the parser breaks do to their environment setup (Duplicate keys etc.)

rucio/lib/rucio/common/config.py

Lines 224 to 227 in 253c2f1

	if sys.version_info < (3, 2):
	self.parser = ConfigParser.SafeConfigParser(os.environ)
	else:
	self.parser = ConfigParser.ConfigParser(defaults=os.environ)

I do not think that it is necessary to load the entire ENV space in there, since the ENV variables we are interested in, are usually directly accessed from the environment.

1. Investigate if this is really needed
2. If not take it out from the Configparser