Merge pull request #74 from cossacklabs/vixentael/fix-c-example-makefile

fix makefile for credential store service

Author: Lagovas

docs/examples/c/mid_hermes/credential_store_service/Makefile

@@ -2,6 +2,7 @@ all:
 	gcc -g -I../../../../../include -L../../../../../build  \
 	main.c \
 	../common/transport.c \
+	../common/session_callback.c \
 	../common/credential_store_client.c \
 	db.c \
 	../../utils/utils.c \