rpcd: update to latest Git head

rpcd: update to latest Git head

3aa81d0 file: access exec timeout via daemon ops structure
7235f34 plugin: store pointer to exec timeout value in the ops structure
ccd7c0a treewide: rename exec_timeout to rpc_exec_timeout
c79ef22 main: fix logic bug when not specifying a timeout option
2cc4b99 file: use global exec timeout instead of own hardcoded limit
ecd1660 exec: increase maximum execution time to 120s

Also expose the socket and timeout options in /etc/config/rpcd for
easier use.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>
(cherry picked from commits 41055551151e12abf8efe710efa4dc025a7b7b6a,
 952b11766cd83898cf8f9626b75141eac6d4ad1a and
 e533fb17061027dca2cc60a9555fc2edb9e832eb)