Fix nut-scanner compilation in some environments

Following the commits 5187dab (common: add some string-related functions) and
e767df5 (common: consolidate some string-related functions), the build rules of
nut-scanner were not updated to also use str.c. Since the libcommon.la
dependency was still there, some environments managed to build cleanly, while
other are failing.  Update build dependencies to fix this situation

Author: aquette

tools/nut-scanner/Makefile.am

@@ -14,14 +14,14 @@ libnutscan_la_SOURCES = scan_nut.c scan_ipmi.c \
 			scan_avahi.c scan_eaton_serial.c nutscan-serial.c \
 			../../drivers/serial.c \
 			../../drivers/bcmxcp_ser.c \
-			../../common/common.c
+			../../common/common.c ../../common/str.c
 libnutscan_la_LIBADD = $(NETLIBS) $(LIBLTDL_LIBS)
 libnutscan_la_LDFLAGS = $(SERLIBS) -version-info 1:0:0
 libnutscan_la_CFLAGS = -I$(top_srcdir)/clients -I$(top_srcdir)/include $(LIBLTDL_CFLAGS) -I$(top_srcdir)/drivers
 
 nut_scanner_SOURCES = nut-scanner.c
 nut_scanner_CFLAGS = -I$(top_srcdir)/clients -I$(top_srcdir)/include
-nut_scanner_LDADD = libnutscan.la ../../common/libcommon.la
+nut_scanner_LDADD = libnutscan.la
 
 if WITH_SSL
   libnutscan_la_CFLAGS += $(LIBSSL_CFLAGS)