Set working directory in systemd service file

By default systemd will execute service with root directory
(or home directory for user instance) which might result in
attempts to create files in unexpected place. Let's set it
to 'osmocom' subdir of state directory
(/var/lib for system instance) instead.

Related: OS#4821
Change-Id: I39c48167cbe74b599c8edc3659e787792cbcfdfd
diff --git a/contrib/systemd/osmo-pcap-client.service b/contrib/systemd/osmo-pcap-client.service
index fd0de75..496358f 100644
--- a/contrib/systemd/osmo-pcap-client.service
+++ b/contrib/systemd/osmo-pcap-client.service
@@ -4,6 +4,8 @@
 [Service]
 Type=simple
 Restart=always
+StateDirectory=osmocom
+WorkingDirectory=%S/osmocom
 ExecStart=/usr/bin/osmo-pcap-client -c /etc/osmocom/osmo-pcap-client.cfg
 RestartSec=2
 
diff --git a/contrib/systemd/osmo-pcap-server.service b/contrib/systemd/osmo-pcap-server.service
index 3094fc4..28345d6 100644
--- a/contrib/systemd/osmo-pcap-server.service
+++ b/contrib/systemd/osmo-pcap-server.service
@@ -4,6 +4,8 @@
 [Service]
 Type=simple
 Restart=always
+StateDirectory=osmocom
+WorkingDirectory=%S/osmocom
 ExecStart=/usr/bin/osmo-pcap-server -c /etc/osmocom/osmo-pcap-server.cfg
 RestartSec=2