Make the pg_upgrade log files contain actual commands
Make the pg_upgrade log files contain actual commands

Now the log file not only contains the output from commands executed by
system(), but also what command it was in the first place.  This
arrangement makes debugging a lot simpler.

arcivanov/postgres-xl,snaga/postgres-xl,snaga/postgres-xl,postmind-net/postgres-xl,snaga/postgres-xl,arcivanov/postgres-xl,postmind-net/postgres-xl,kmjungersen/PostgresXL,kmjungersen/PostgresXL,snaga/postgres-xl,kmjungersen/PostgresXL,postmind-net/postgres-xl,arcivanov/postgres-xl,postmind-net/postgres-xl,arcivanov/postgres-xl,arcivanov/postgres-xl,postmind-net/postgres-xl,kmjungersen/PostgresXL,snaga/postgres-xl,kmjungersen/PostgresXL,arcivanov/postgres-xl