Address inconsistency with Symbols and Strings for Job#status in machete

[ericfranz]

Summary:

• OSC::Machete::Job#status returns a symbol
• In other places we use a string
• symbols stored in the database are apparently stored as yaml or as string formats
• queries directly with the database need to use the string (AFAIK)
• comparisons between symbols and strings fail

This commit addressed a problem that this inconsistency caused:

https://github.com/AweSim-OSC/osc-machete/commit/0feaf68afa071276372e96e98c9506972a27db02

This inconsistency might have been introduced by an earlier confusion on how ActiveRecord persisted symbols to a database column. When we address rearchitecture, including using a status value object, we just need to make sure that if we serialize that status value and deserialize it later it has a consistent value.

[ericfranz]

32 will address this