resolve an issue found by cppcheck:
authorIlya Shipitsin <chipitsine@gmail.com>
Wed, 31 May 2017 09:32:59 +0000 (14:32 +0500)
committerIlya Shipitsin <chipitsine@gmail.com>
Wed, 31 May 2017 09:32:59 +0000 (14:32 +0500)
commit06edf5f7c58c272cddfcf545321b0cf06faf79ca
tree7262e70fc0894ae35b05d72c2789b534be6023bf
parent48163a27dbbaa73c149c7df2c1a3e9afb3d3c34a
resolve an issue found by cppcheck:

[channels/tsmf/client/tsmf_main.c:89] -> [channels/tsmf/client/tsmf_main.c:95]: (warning) Either the condition '!callback' is redundant or there is possible null pointer dereference: callback.
channels/tsmf/client/tsmf_main.c