build: pkg anti-pattern: use defaults

Use the defaults in the pkg check where the default error message is
sufficient to identify which package is missing.

Change-Id: I505ebc57cc86595df294d6e9cf7e57513ffc3aa5
Signed-off-by: Patrick Venture <venture@google.com>
diff --git a/configure.ac b/configure.ac
index 4fa36d3..8e31832 100755
--- a/configure.ac
+++ b/configure.ac
@@ -12,12 +12,9 @@
 
 # Check for libraries
 PKG_CHECK_MODULES([SYSTEMD], [libsystemd >= 221])
-PKG_CHECK_MODULES([PHOSPHOR_DBUS_INTERFACES], [phosphor-dbus-interfaces],,\
-    AC_MSG_ERROR(["Requires phosphor-dbus-interfaces package."]))
-PKG_CHECK_MODULES([SDBUSPLUS], [sdbusplus],,
-    AC_MSG_ERROR(["Requires sdbusplus package."]))
-PKG_CHECK_MODULES([PHOSPHOR_LOGGING], [phosphor-logging],,\
-    AC_MSG_ERROR(["Requires phosphor-logging package."]))
+PKG_CHECK_MODULES([PHOSPHOR_DBUS_INTERFACES], [phosphor-dbus-interfaces])
+PKG_CHECK_MODULES([SDBUSPLUS], [sdbusplus])
+PKG_CHECK_MODULES([PHOSPHOR_LOGGING], [phosphor-logging])
 # Check for sdbus++
 AC_PATH_PROG([SDBUSPLUSPLUS], [sdbus++])
 AS_IF([test "x$SDBUSPLUSPLUS" == "x"],