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/merge-recursive.c b/merge-recursive.c
index 6bc3eac..245232a 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -498,8 +498,7 @@
 		if (type != OBJ_BLOB)
 			die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 		if (S_ISREG(mode)) {
-			struct strbuf strbuf;
-			strbuf_init(&strbuf, 0);
+			struct strbuf strbuf = STRBUF_INIT;
 			if (convert_to_working_tree(path, buf, size, &strbuf)) {
 				free(buf);
 				size = strbuf.len;