move flexelint silencing from global to module

we see this issue in two places (for libvcc and varnishd), hope this
will silence both

bin/varnishd/flint.lnt

@@ -172,9 +172,7 @@
 -esym(759, HTTP_IterHdrPack)	// Could be moved to module
 -esym(759, ObjGetU32)		// Could be moved to module
 -esym(759, Lck_DestroyClass)	// Could be moved to module
--esym(759, SYMTAB_NOERR)	// Could be moved to module
 -esym(765, HTTP_IterHdrPack)	// Could be made static
 -esym(765, ObjGetU32)		// Could be made static
 -esym(765, Lck_DestroyClass)	// Could be made static
--esym(765, SYMTAB_NOERR)	// Could be made static
 -esum(769, obj_attr::OA__MAX)	// Not referenced

lib/libvcc/vcc_symb.c

@@ -27,6 +27,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  */
+/*lint -save -esym(759, SYMTAB_NOERR) -esym(765, SYMTAB_NOERR)*/
 
 #include "config.h"
 
@@ -534,3 +535,4 @@ VCC_HandleSymbol(struct vcc *tl, vcc_type_t fmt, const char *pfx)
 		sym->def_b = t;
 	return (sym);
 }
+/*lint -restore */