optimize check for pygpgme

[kpankonen]

We were doing some profiling to troubleshoot slow puppet runs and noticed that this fact was taking longer than we'd expect. This change speeds it up by only checking for the pygpgme package

[root@389f9a260f7a /]$ time (rpm -qa |grep pygpgme) pygpgme-0.3-9.el7.x86_64 real	0m0.867s user	0m0.135s sys	0m0.065s

[root@389f9a260f7a /]$ time (rpm -q pygpgme) pygpgme-0.3-9.el7.x86_64 real	0m0.033s user	0m0.024s sys	0m0.009s

[root@6f1cf2b76513 /]$ rpm -q fakepackage package fakepackage is not installed

[yakirgb]

Thank you @kpankonen , just added this fix to our internal repo