fuzz: Remove unnecessary calls to set plugin dirs

All the plugins are linked statically into the binaries, so there
is no reason to set the directories that are only required when loading
them from files.

fuzz/Makefile.am

@@ -7,8 +7,7 @@ AM_CPPFLAGS = @CPPFLAGS@ \
 	-I$(top_srcdir)/src/libtpmtss \
 	-I$(top_srcdir)/src/libtnccs \
 	-I$(top_srcdir)/src/libtnccs/plugins/tnccs_20 \
-	-I$(top_srcdir)/src/libradius \
-	-DPLUGINDIR=\""$(abs_top_builddir)/src/libstrongswan/plugins\""
+	-I$(top_srcdir)/src/libradius
 
 fuzz_cppflags_def = ${AM_CPPFLAGS} \
 	-DPLUGINS="\"${fd_plugins}\""