libsparse: rename symbols that conflict with libext4_utils

Until ext4_utils switches to using libsparse, libext4_utils defines some
of the same symbols as libsparse.  Fastboot links statically against
both of them, and there is no easy way to make the symbols hidden, so
just rename them in libsparse.

Change-Id: Idc2cfe20efe3c3a7fb8233f453a89bbbeb0dcc8b
diff --git a/libsparse/output_file.c b/libsparse/output_file.c
index dc56149..b5ae419 100644
--- a/libsparse/output_file.c
+++ b/libsparse/output_file.c
@@ -541,7 +541,7 @@
 		.write_end_chunk = write_normal_end_chunk,
 };
 
-void close_output_file(struct output_file *out)
+void output_file_close(struct output_file *out)
 {
 	int ret;
 
@@ -638,7 +638,7 @@
 	return &outn->out;
 }
 
-struct output_file *open_output_callback(int (*write)(void *, const void *, int),
+struct output_file *output_file_open_callback(int (*write)(void *, const void *, int),
 		void *priv, unsigned int block_size, int64_t len, int gz, int sparse,
 		int chunks, int crc)
 {
@@ -664,7 +664,7 @@
 	return &outc->out;
 }
 
-struct output_file *open_output_fd(int fd, unsigned int block_size, int64_t len,
+struct output_file *output_file_open_fd(int fd, unsigned int block_size, int64_t len,
 		int gz, int sparse, int chunks, int crc)
 {
 	int ret;