Do "make clean" before "make"
Do "make clean" before "make"

Travis-CI tests are failing because of object files generated by previous builds. Let's do a cleanup before each build.

bmagistro/yara,cblichmann/yara,cblichmann/yara,pombredanne/yara,rednaga/yara,jpypi/yara,plusvic/yara,cblichmann/yara,kallanreed/yara,cblichmann/yara,hillu/yara,plusvic/yara,wxsBSD/yara,hillu/yara,VirusTotal/yara,MeteorAdminz/yara,VirusTotal/yara,kallanreed/yara,jpypi/yara,pombredanne/yara,cblichmann/yara,hillu/yara,rednaga/yara,msuvajac/yara,kallanreed/yara,pombredanne/yara,bmagistro/yara,hillu/yara,pombredanne/yara,wxsBSD/yara,tanium/yara,tanium/yara,hillu/yara,VirusTotal/yara,VirusTotal/yara,msuvajac/yara,jpypi/yara,pombredanne/yara,wxsBSD/yara,MeteorAdminz/yara,rednaga/yara,msuvajac/yara,plusvic/yara,plusvic/yara,tanium/yara,wxsBSD/yara,MeteorAdminz/yara,VirusTotal/yara,wxsBSD/yara,plusvic/yara,bmagistro/yara