The opencv element includes were full of duplicates and uneeded headers.
For example a few elements that stopped using gstcvopencvutils still
included that header file.
We know that the gchar arrays contain at least one string. Furthermore,
g_strfreev() checks if the array is NULL and simply returns if it is.
Hence, there is no need to check if the array is empty before using
g_strfreev().
CID 1327412-1327415
