Update wordcount.c
Update wordcount.c

Fix 2 issues that happen during the string fetching operation from file:
1. Add the null-termination character '\0' to fix the strange monster characters that happen at the end of a word 
2. Use calloc(0, sizeof(char)) to ensure re-instantiating a previously free-ed character arrays, this fix the issue whether some words may include characters from previous words
jeffrey-garcia/C-MapReduce