Prepare for unstable upload: set ABI to 1 and drop ~exp1 from the version

debian/changelog

@@ -1,4 +1,4 @@
-linux (4.5.1-1~exp1) UNRELEASED; urgency=medium
+linux (4.5.1-1) UNRELEASED; urgency=medium
 
   * New upstream stable update:
     https://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.5.1
@@ -232,6 +232,7 @@ linux (4.5.1-1~exp1) UNRELEASED; urgency=medium
   * Disable UNUSED_SYMBOLS; it is now itself unused
   * linux-support: Include udeb configuration from debian/installer for use
     by the linux-signed package
+  * Set ABI to 1
 
   [ Aurelien Jarno ]
   * [mipsel/mips/config.loongson-2f] Disable VIDEO_CX23885, VIDEO_IVTV,

debian/config/defines

@@ -1,5 +1,5 @@
 [abi]
-abiname: trunk
+abiname: 1
 
 [base]
 arches: