Fix conflicting types of temporary variables caused compilation errors

[eniac111]

The compiler was failing with this error:

ude/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -pthread -I/usr/include/gconf/2 -I/usr/include/dbus-1.0 -I/usr/lib/x86_64-linux-gnu/dbus-1.0/include -I/usr/include/libmount -I/usr/include/blkid -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -I/usr/include/glib-2.0 -I/usr/lib/x86_64-linux-gnu/glib-2.0/include -I/usr/include/icd -Wdate-time -D_FORTIFY_SOURCE=2 -Wall -Wextra -Wno-unused-function -Wno-unused-parameter -Werror -c wpaicd.c  -fPIC -DPIC -o .libs/wpaicd.o
wpaicd.c: In function ‘on_scan_done’:
wpaicd.c:623:15: error: conflicting types for ‘tmp’
  623 |     GVariant *tmp = g_variant_get_child_value(bsss, 0);
      |               ^~~
wpaicd.c:597:12: note: previous definition of ‘tmp’ was here
  597 |     gchar *tmp = g_variant_print(parameters, TRUE);
      |            ^~~
make[3]: *** [Makefile:461: wpaicd.lo] Error 1
make[3]: Leaving directory '/root/packages/libicd-network-wpasupplicant/src'
make[2]: *** [Makefile:532: all-recursive] Error 1
make[2]: Leaving directory '/root/packages/libicd-network-wpasupplicant'
make[1]: *** [Makefile:408: all] Error 2
make[1]: Leaving directory '/root/packages/libicd-network-wpasupplicant'
dh_auto_build: error: make -j1 returned exit code 2
make: *** [debian/rules:6: build] Error 25
dpkg-buildpackage: error: debian/rules build subprocess returned exit status 2
debuild: fatal error at line 1182:
dpkg-buildpackage -us -uc -ui -b failed