bus: shorten bus type

Create an alias `sdbusplus::bus_t` to `sdbusplus::bus::bus` to reduce
duplication.

Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
Change-Id: I9f17892eed5112d49469498614884c02bba86011
diff --git a/test/bus/match.cpp b/test/bus/match.cpp
index ee76972..2d95cf9 100644
--- a/test/bus/match.cpp
+++ b/test/bus/match.cpp
@@ -6,7 +6,7 @@
 class Match : public ::testing::Test
 {
   protected:
-    sdbusplus::bus::bus bus = sdbusplus::bus::new_bus();
+    sdbusplus::bus_t bus = sdbusplus::bus::new_bus();
 
     static constexpr auto busName = "xyz.openbmc_project.sdbusplus.test.Match";
 
diff --git a/test/message/call.cpp b/test/message/call.cpp
index 0ef015f..f0122ee 100644
--- a/test/message/call.cpp
+++ b/test/message/call.cpp
@@ -20,13 +20,13 @@
     m.read(globalId);
 }
 
-message newBusIdReq(bus::bus& b)
+message newBusIdReq(bus_t& b)
 {
     return b.new_method_call("org.freedesktop.DBus", "/org/freedesktop/DBus",
                              "org.freedesktop.DBus", "GetId");
 }
 
-std::string syncBusId(bus::bus& b)
+std::string syncBusId(bus_t& b)
 {
     std::string ret;
     newBusIdReq(b).call().read(ret);
diff --git a/test/server/message_variant.cpp b/test/server/message_variant.cpp
index 0fcde8d..2ddfac4 100644
--- a/test/server/message_variant.cpp
+++ b/test/server/message_variant.cpp
@@ -8,7 +8,7 @@
 
 struct Object : public ::testing::Test
 {
-    sdbusplus::bus::bus bus = sdbusplus::bus::new_default();
+    sdbusplus::bus_t bus = sdbusplus::bus::new_default();
     sdbusplus::message_t msg = bus.new_method_call(
         "xyz.openbmc_project.sdbusplus.test.Object",
         "/xyz/openbmc_project/sdbusplus/test/object",
diff --git a/test/server/object.cpp b/test/server/object.cpp
index 76e077d..abbb412 100644
--- a/test/server/object.cpp
+++ b/test/server/object.cpp
@@ -16,7 +16,7 @@
 {
   protected:
     sdbusplus::SdBusMock sdbusMock;
-    sdbusplus::bus::bus bus = sdbusplus::get_mocked_new(&sdbusMock);
+    sdbusplus::bus_t bus = sdbusplus::get_mocked_new(&sdbusMock);
 
     static constexpr auto busName = "xyz.openbmc_project.sdbusplus.test.Object";
     static constexpr auto objPath = "/xyz/openbmc_project/sdbusplus/test";