misc: fix build for libgit > 1.8.0

Change-Id: I5576412901a12be74395823a6abf7954bbd72b73

test/unitTest/conversation/conversationcommon.cpp

@@ -249,7 +249,13 @@ commitInRepo(const std::string& path, std::shared_ptr<JamiAccount> account, cons
     GitCommit head_commit {head_ptr, git_commit_free};
 
     git_buf to_sign = {};
+#if( LIBGIT2_VER_MAJOR > 1 ) || ( LIBGIT2_VER_MAJOR == 1 && LIBGIT2_VER_MINOR >= 8 )
+    // For libgit2 version 1.8.0 and above
+    git_commit* const head_ref[1] = {head_commit.get()};
+#else
+    // For libgit2 versions older than 1.8.0
     const git_commit* head_ref[1] = {head_commit.get()};
+#endif
     if (git_commit_create_buffer(
             &to_sign, repo, sig.get(), sig.get(), nullptr, msg.c_str(), tree.get(), 1, &head_ref[0])
         < 0) {