maint: update .mailmap for recent contributions

Deepak Shetty has changed preferred email address since prior
contributions.
Signed-off-by: NEric Blake <eblake@redhat.com>

.mailmap

@@ -7,6 +7,8 @@
 <charles_duffy@messageone.com> <charles@dyfis.net>
 <claudio.bley@gmail.com> <cbley@av-test.de>
 <dfj@redhat.com> <dfj@dfj.bne.redhat.com>
+<dpkshetty@gmail.com> <deepakcs@linux.vnet.ibm.com>
+<dpkshetty@gmail.com> <deepakcs@redhat.com>
 <eblake@redhat.com> <ebb9@byu.net>
 <gdolley@arpnetworks.com> <gdolley@ucla.edu>
 <gerhard.stenzel@de.ibm.com> <gstenzel@linux.vnet.ibm.com>
@@ -58,3 +60,4 @@ Marco Bozzolan <bozzolan@gmail.com>
 Marco Bozzolan <redshift@gmx.com>
 Pritesh Kothari <pritesh.kothari@sun.com>
 Wang Yufei (James) <james.wangyufei@huawei.com>
+Deepak C Shetty <dpkshetty@gmail.com>