PM-802 - When using GLite remote_cerequirements string was enclode in double quotes. So when environment variable values which contained double quotes or spaces were not properly translated to the PBS script.

The changes support environment variable values with spaces and double quotes in their values.

Single quotes are not supported as condor takes value from the sub file and encloses them in single quotes. i.e.
MYENV="X=Y,A=B"
  is altered to
MYENV='"X=Y,A=B"'

Backslashes are not supported as even when properly encoded in PBS script they get ignored by PBS i.e
MYENV="X=A\B"
  is written to PBS file as
\#PBS -v X=A\\B but yet the env. value when read inside the scrip yields AB

The above changes will not compatible if and when Condor makes changes to fix the way it translates string values.
Merge branch '4.4'