length of local variable file in GPTLget_memusage too short

Some experiments on derecho using an old version of CIME are getting the error
get_memusage: pid NNNNNNN is too large
where NNNNNNN is a number larger than 999999.
The check on the pid appears to be there to ensure that writing to the local char array `file` a string containing the pid doesn't write past the end of `file`.
The error was addressed in https://github.com/ESMCI/cime/commit/96b4dd13005642fb460c944a872999487ac56b09 by changing the conditional `pid > 999999` to `pid <= 0`.
However, if `pid` exceeds 999999, as is currently happening on derecho, then the write to `file` will silently write past the end of `file`.
It seems like the length of the variable `file` should be increased to accommodate 7 digit pids.