Check an edge case when read(2) returns 0

We might end up in an infinite loop if read(2) reached EOF unexpectedly.
The problematic code in uncrypt mentioned in the bug has been fixed
by switching to libbase ReadFully(). So I grepped through the recovery
code and fixed some other occurences of the issue.

Bug: 31073201
Change-Id: Ib867029158ba23363b8f85d61c25058a635c5a6b

applypatch/applypatch.cpp

@@ -336,6 +336,9 @@ int WriteToPartition(const unsigned char* data, size_t len, const char* target)
                     printf("verify read error %s at %zu: %s\n",
                            partition, p, strerror(errno));
                     return -1;
+                } else if (read_count == 0) {
+                    printf("verify read reached unexpected EOF, %s at %zu\n", partition, p);
+                    return -1;
                 }
                 if (static_cast<size_t>(read_count) < to_read) {
                     printf("short verify read %s at %zu: %zd %zu %s\n",