adb: stop using adbkey.pub.

An adbkey/adbkey.pub pair that doesn't match up results in a
hard-to-diagnose scenario where "Always allow from this computer"
doesn't work. The private key contains all of the information that's
in the public key, so just extract the public key out of the private
key instead of storing them separately.

Bug: http://b/119634232
Test: rm ~/.android/adbkey.pub; adb kill-server; adb shell true
Test: rm ~/.android/adbkey*; adb kill-server; adb shell true
Change-Id: I0ae9033dbcd119c12cfb2b3977f1f1954ac800c1
diff --git a/adb/client/commandline.cpp b/adb/client/commandline.cpp
index b5bed28..c11052d 100644
--- a/adb/client/commandline.cpp
+++ b/adb/client/commandline.cpp
@@ -185,7 +185,6 @@
         " enable-verity            re-enable dm-verity checking on userdebug builds\n"
         " keygen FILE\n"
         "     generate adb public/private key; private key stored in FILE,\n"
-        "     public key stored in FILE.pub (existing files overwritten)\n"
         "\n"
         "scripting:\n"
         " wait-for[-TRANSPORT]-STATE\n"
@@ -1756,14 +1755,14 @@
         // Always print key generation information for keygen command.
         adb_trace_enable(AUTH);
         return adb_auth_keygen(argv[1]);
-    }
-    else if (!strcmp(argv[0], "jdwp")) {
+    } else if (!strcmp(argv[0], "pubkey")) {
+        if (argc != 2) error_exit("pubkey requires an argument");
+        return adb_auth_pubkey(argv[1]);
+    } else if (!strcmp(argv[0], "jdwp")) {
         return adb_connect_command("jdwp");
-    }
-    else if (!strcmp(argv[0], "track-jdwp")) {
+    } else if (!strcmp(argv[0], "track-jdwp")) {
         return adb_connect_command("track-jdwp");
-    }
-    else if (!strcmp(argv[0], "track-devices")) {
+    } else if (!strcmp(argv[0], "track-devices")) {
         return adb_connect_command("host:track-devices");
     } else if (!strcmp(argv[0], "raw")) {
         if (argc != 2) {
@@ -1772,13 +1771,11 @@
         return adb_connect_command(argv[1]);
     }
 
-
     /* "adb /?" is a common idiom under Windows */
     else if (!strcmp(argv[0], "--help") || !strcmp(argv[0], "help") || !strcmp(argv[0], "/?")) {
         help();
         return 0;
-    }
-    else if (!strcmp(argv[0], "--version") || !strcmp(argv[0], "version")) {
+    } else if (!strcmp(argv[0], "--version") || !strcmp(argv[0], "version")) {
         fprintf(stdout, "%s", adb_version().c_str());
         return 0;
     } else if (!strcmp(argv[0], "features")) {