remove bicycle from lua code

https://rpm-software-management.github.io/rpm/manual/lua

glibc.spec

@@ -125,23 +125,13 @@
 -- https://github.com/projectatomic/rpm-ostree/pull/1869 \
 -- If we add new lua actions to the %%post code we should coordinate \
 -- with rpm-ostree and ensure that their glibc install is functional. \
-function post_exec (program, ...) \
-  local pid = posix.fork () \
-  if pid == 0 then \
-    posix.exec (program, ...) \
-    assert (nil) \
-  elseif pid > 0 then \
-    posix.wait (pid) \
-  end \
-end \
-\
 function update_gconv_modules_cache () \
   local iconv_dir = "%{_libdir}/gconv" \
   local iconv_cache = iconv_dir .. "/gconv-modules.cache" \
   local iconv_modules = iconv_dir .. "/gconv-modules" \
   if (posix.utime (iconv_modules) == 0) then \
     if (posix.utime (iconv_cache) == 0) then \
-      post_exec ("%{_sbindir}/iconvconfig", \
+      rpm.execute ("%{_sbindir}/iconvconfig", \
 	 "-o", iconv_cache, \
 	 "--nostdlib", \
 	 iconv_dir) \
@@ -438,8 +428,10 @@ end
 -- If the format of the cache changes then we need to rebuild
 -- the cache early to avoid any problems running binaries with
 -- the new glibc.
--- Note: We use _prefix because Fedora's UsrMove says so.
-post_exec ("/sbin/ldconfig")
+-- "-v" here for debugging (maybe remove it later)
+if not rpm.execute("/sbin/ldconfig", "-v") then
+   io.stdout:write ("Error: call to /sbin/ldconfig failed.\n")
+end
 
 -- (4) Update gconv modules cache.
 -- If the /usr/lib/gconv/gconv-modules.cache exists, then update it