stack: Fixes cppcheck issue in ocserverrequest
stack: Fixes cppcheck issue in ocserverrequest

This patch fixes the the below issue reported by 
cppcheck tool in stack dir:
"(error) Possible null pointer dereference: 
ehResponse - otherwise it is redundant to check if 
ehResponse is null at line 445
"

Dereferencing of ehResponse is done after NULL check.

Change-Id: I9cc20ce2386b5bdb08c4d9f9dbd2d143040f9a0f
Signed-off-by: Ravi Nanjundappa <2b6ed790834a9696042087f8677f81934b9f07fd@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/1509
Reviewed-by: Erich Keane <ec9f61fe526c14bb62c55d7c978f025ee6b3583d@intel.com>
Tested-by: Erich Keane <ec9f61fe526c14bb62c55d7c978f025ee6b3583d@intel.com>

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