client: Add support for local cache dirty/damaged checking
client: Add support for local cache dirty/damaged checking

- At run and upload time, check whether the local cache is dirty and run
a full validation if so

- If the local cache is damaged at run time, tell the user and ask them if
they wish to continue

- At upload time, check if the local cache is damaged and error out as early
as possible (i.e., before the memory image is encoded)

- Remove unused variable

cmusatyalab/openisr,cmusatyalab/openisr,cmusatyalab/openisr,cmusatyalab/openisr,cmusatyalab/openisr