Update location for multicast tests.

While running networktest for multicast ;  "mc_member" test displays the
following error message multiple times
"cat: /opt/ltp/testcases/inetwork/multicast/mc_menmber/ManyGroups: No
such file or directory".
This is Because variable "TCsrc" is exported with incorrect path. Looks
like previously LTP test scripts installed and ran directly from source
directory . Now it installs mulicast test binary and script files to
"$LTPROOT/testcases/bin" directory. Hence the variable "TCsrc" needed to
be exported with above mentioned install path.

Signed-off-by:  Sumit Dhoot <sumitbd@linsyssoft.com>
Acked-by: Garrett Cooper <yanegomi@gmail.com>
diff --git a/runtest/multicast b/runtest/multicast
index 14e7828..08b65f7 100644
--- a/runtest/multicast
+++ b/runtest/multicast
@@ -3,6 +3,6 @@
 # PLEASE READ THE README FILE IN /multicast BEFORE RUNNING THESE.
 #
 mc_cmds mc_cmds
-mc_commo export TCsrc=$LTPROOT/testcases/network/multicast/mc_commo; mc_commo
-mc_member export TCsrc=$LTPROOT/testcases/network/multicast/mc_member; mc_member
-mc_opts export TCsrc=$LTPROOT/testcases/network/multicast/mc_opts; mc_opts
+mc_commo export TCsrc=$LTPROOT/testcases/bin; mc_commo
+mc_member export TCsrc=$LTPROOT/testcases/bin; mc_member
+mc_opts export TCsrc=$LTPROOT/testcases/bin; mc_opts