dm snapshot: free exception store on init failure
dm snapshot: free exception store on init failure

While initializing the snapshot module, if we fail to register
the snapshot target then we must back-out the exception store
module initialization.

Cc: 4fbacc2fa0ffdbb11bf1ad6925b886ebd08dd15f@kernel.org
Signed-off-by: Jonathan Brassow <b97f60d0348d610aa36b7618afc2a1f9fec67557@redhat.com>
Reviewed-by: Mikulas Patocka <52f8f9962b7f38d8269c63c0859d68147c8d10f0@redhat.com>
Reviewed-by: Mike Snitzer <85e533f2e78486213c4d69f71462342ec0c62734@redhat.com>
Signed-off-by: Alasdair G Kergon <620085386a2c64ec2f1d43bef997c15003f13da2@redhat.com>

KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,TeamVee-Kanas/android_kernel_samsung_kanas,KristFoundation/Programs,KristFoundation/Programs