Replace calls to strbuf_init(&foo, 0) with STRBUF_INIT initializer

Many call sites use strbuf_init(&foo, 0) to initialize local
strbuf variable "foo" which has not been accessed since its
declaration. These can be replaced with a static initialization
using the STRBUF_INIT macro which is just as readable, saves a
function call, and takes up fewer lines.

Signed-off-by: Brandon Casey <casey@nrlssc.navy.mil>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
diff --git a/hash-object.c b/hash-object.c
index a4d127c..20937ff 100644
--- a/hash-object.c
+++ b/hash-object.c
@@ -34,10 +34,8 @@
 
 static void hash_stdin_paths(const char *type, int write_objects)
 {
-	struct strbuf buf, nbuf;
+	struct strbuf buf = STRBUF_INIT, nbuf = STRBUF_INIT;
 
-	strbuf_init(&buf, 0);
-	strbuf_init(&nbuf, 0);
 	while (strbuf_getline(&buf, stdin, '\n') != EOF) {
 		if (buf.buf[0] == '"') {
 			strbuf_reset(&nbuf);