Fix log printing always shows the role as child under daemonize

[enjoy-binbin]

In #1282, we init server.pid earlier to keep log message role
consistent, but we forgot to consider daemonize. In daemonize
mode, we will always print the child role.

We need to reset server.pid after daemonize(), otherwise the
log printing role will always be the child. It also causes a
incorrect server.pid value, affecting the concatenation of
some pid names.

[zuiderkwast]

Great, thanks!

@azuredream FYI

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 3 lines in your changes missing coverage. Please review.

Project coverage is 70.69%. Comparing base (2df56d8) to head (0a98333).
Report is 1 commits behind head on unstable.

Files with missing lines	Patch %	Lines
src/server.c	0.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##           unstable    #1301   +/-   ##
=========================================
  Coverage     70.69%   70.69%           
=========================================
  Files           114      114           
  Lines         63161    63163    +2     
=========================================
+ Hits          44650    44656    +6     
+ Misses        18511    18507    -4     

Files with missing lines	Coverage Δ
src/server.c	87.64% <0.00%> (-0.06%)	⬇️

... and 11 files with indirect coverage changes