Fix buffer overflow on #include of an empty file
Fix buffer overflow on #include of an empty file

When reading an empty file, fgets returns NULL without writing to the
buffer. So the buffer contains garbage.

The get_file_contents() function then just returns a pointer to the
buffer, and the caller tries to analyze this garbage. The result
depends on actual garbage.

Fix it by assigning '\0' to the first character of the buffer.

linas/link-grammar,linas/link-grammar,ampli/link-grammar,opencog/link-grammar,linas/link-grammar,opencog/link-grammar,opencog/link-grammar,opencog/link-grammar,ampli/link-grammar,opencog/link-grammar,linas/link-grammar,linas/link-grammar,ampli/link-grammar,ampli/link-grammar,linas/link-grammar,opencog/link-grammar,opencog/link-grammar,ampli/link-grammar,ampli/link-grammar,ampli/link-grammar,linas/link-grammar,linas/link-grammar,opencog/link-grammar,ampli/link-grammar,opencog/link-grammar,ampli/link-grammar,linas/link-grammar