UHURA 37t

Summary
The pilot as been updated to handle badly formed metadata. E.g. if the metadata contains tags like:

<META type="string" name="postExec" value="['from AthenaCommon.AlgSequence import AlgSequence;AlgSequence(\"AthAlgSeq\").TimeOut=0']">

the "-sign preceeding AthAlgSeq will close the value string, and the python xml parser will fail. The pilot occationally needs to process the metadata file to read guids that are missing from the PFC.

Example of a job (which previously failed) run by the updated pilot:
http://panda.cern.ch:25980/server/pandamon/query?job=1018871000

Version info
Created prepareMetadata(), preprocessMetadata() (pUtil)
Pilot is now removing badly formed metadata from metadata.xml (pUtil)