netdata: allow execution without a config file

[womfoo]

Motivation for this change

netdata does not work when not passed a configuration file. I've also updated the web_access.patch for version 1.4 which was removed in the latest commit.

# netdata
16-10-25 15:13:28: ERROR: netdata: Cannot open file '/nix/store/8cgjg5isb8dp72ww9mbgkgifq9d33j8v-netdata-1.4.0/etc/netdata/netdata.conf' (errno 2, No such file or directory)
16-10-25 15:13:28: INFO: netdata: System has 8 processors.
16-10-25 15:13:28: INFO: netdata: System supports 32768 pids.
16-10-25 15:13:28: ERROR: netdata: Group 'nobody' is not present. Ignoring option.
16-10-25 15:13:28: ERROR: netdata: Cannot open file '/nix/store/8cgjg5isb8dp72ww9mbgkgifq9d33j8v-netdata-1.4.0/var/log/netdata/debug.log'. Leaving 1 to its default. (errno 30, Read-only file system)
16-10-25 15:13:28: ERROR: netdata: Cannot open file '/nix/store/8cgjg5isb8dp72ww9mbgkgifq9d33j8v-netdata-1.4.0/var/log/netdata/error.log'. Leaving 2 to its default. (errno 30, Read-only file system)
16-10-25 15:13:28: ERROR: netdata: Cannot open file '/nix/store/8cgjg5isb8dp72ww9mbgkgifq9d33j8v-netdata-1.4.0/var/log/netdata/access.log'. Leaving -1 to its default. (errno 30, Read-only file system)
16-10-25 15:13:28: INFO: netdata: Adjusted my Out-Of-Memory score to 1000.
16-10-25 15:13:28: INFO: netdata: Adjusted my scheduling priority to IDLE.
16-10-25 15:13:28: INFO: netdata: 
Successfully became user 'nobody'.
16-10-25 15:13:28: INFO: netdata: NetData started on pid 31914
16-10-25 15:13:28: FATAL: netdata: Cannot create unique machine id file '/nix/store/8cgjg5isb8dp72ww9mbgkgifq9d33j8v-netdata-1.4.0/var/lib/netdata/registry/netdata.public.unique.id'. Please fix this. # : Read-only file system

16-10-25 15:13:28: INFO: netdata: Called: netdata_cleanup_and_exit()
16-10-25 15:13:28: INFO: netdata: Saving database...
16-10-25 15:13:28: INFO: netdata: NetData exiting. Bye bye...

Also cleaned up the preConfigure section as the libraries appear to be linked OK.

$ ldd result/bin/netdata 
    linux-vdso.so.1 (0x00007ffdb91f1000)
    libm.so.6 => /nix/store/23vndix3mzcyw84kag06h8fh464g32nq-glibc-2.24/lib/libm.so.6 (0x00007efdf5d8d000)
    libz.so.1 => /nix/store/caz03y58cyrqn4i5ckdw4i21g9sdjb18-zlib-1.2.8/lib/libz.so.1 (0x00007efdf5b77000)
    libuuid.so.1 => /nix/store/1dyxjvsdnq15sc2ikfibfffvf4l6lq3c-util-linux-2.28.1/lib/libuuid.so.1 (0x00007efdf5972000)
    libpthread.so.0 => /nix/store/23vndix3mzcyw84kag06h8fh464g32nq-glibc-2.24/lib/libpthread.so.0 (0x00007efdf5755000)
    libc.so.6 => /nix/store/23vndix3mzcyw84kag06h8fh464g32nq-glibc-2.24/lib/libc.so.6 (0x00007efdf53b7000)
    /nix/store/23vndix3mzcyw84kag06h8fh464g32nq-glibc-2.24/lib/ld-linux-x86-64.so.2 (0x00007efdf6092000)

Things done

• Tested using sandboxing
  (nix.useSandbox on NixOS,
  or option build-use-sandbox in nix.conf
  on non-NixOS)
• Built on platform(s)
  • NixOS
  • OS X
  • Linux
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Fits CONTRIBUTING.md.

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[mention-bot]

@womfoo, thanks for your PR! By analyzing the history of the files in this pull request, we identified @derchrisuk and @lethalman to be potential reviewers.