meson: switch code dependency to libsystemd

For a while now systemd has packaged a separate `libsystemd`.  For
meson dependency, `systemd` should be used when looking for systemd
service file paths and `libsystemd` should be used for `sd_*` functions.

Update the dependency accordingly.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I6cd50bda0f02315469fac81d5a110a6383feb327
diff --git a/meson.build b/meson.build
index 3e0a43a..b5a78c0 100644
--- a/meson.build
+++ b/meson.build
@@ -12,7 +12,7 @@
 
 # Dependencies
 phosphor_logging_dep = dependency('phosphor-logging')
-systemd = dependency('systemd')
+libsystemd = dependency('libsystemd')
 sdbusplus_dep = dependency('sdbusplus', required : false, include_type: 'system')
 ipmid_dep = dependency('libipmid')
 
@@ -30,7 +30,7 @@
   include_directories: root_inc,
   dependencies: [
     phosphor_logging_dep,
-    systemd,
+    libsystemd,
     sdbusplus_dep,
     ipmid_dep,
   ])